Here’s the short version:
If you grew up poor and can’t mentally justify spending a month of rent in urban California on a single television, if you’re poor as heck right now but could conceivably afford this television, if you’ve never owned a 4k TV, if you’ve never owned an especially large TV, you will not be disappointed by this gigantic freaking monstrosity of a display. It nicely upscales 1080p content, it has a nice frame rate, it has passable speakers you can hear the bass on, and as someone who is picky about delay to the point of 25ms being effectively unusable for music-based games I am very happy with the “game mode” option that removes the delay typically associated with HDMI displays. It is a good TV and everyone in my family, which includes two audio people and a visual artist, is extremely happy with it.

The detailed version:

Given the extremely low cost compared to similarly sized TVs it is surprisingly high quality.
The remote is minimal, comfortable, and easy to use.
Has a phone app in case you’re one of the many people who habitually misplace the remote. App does exactly the same things the remote does.
The speakers kinda suck at low volumes, but it’s whatever. If you care about audio quality go buy some fancy external hookups. It’s good enough that I can bump the Thumper soundtrack and it’s still a decent listening quality. Actually plays tones below 200Hz and does so cleanly, so it’s better than most TVs I’ve had.
It has a “game mode” that it claims will affect the picture quality, but does not noticeably do, and the lack of delay is such that it is not noticeable to me, a musician to whom 25ms of delay is unacceptably bad and unusable. I’m actually able to play Thumper on the Nintendo Switch with no problems whereas with my previous TV it was so bad that I opted instead to play on console with headphones. This is the feature that I love the most about this TV.
The upscaling is such that on my gaming PC I saw no difference between 4k and 1080p when playing GTA5 (except for the frame rate when large distances or a large number of objects are visible, which is entirely due to the fact that I’m playing it on a GTX1060).
It has a lot of service integrations, such as Netflix, Hulu, Amazon Instant Video, Google Play Movies, and a few others.
IT’S HUGE OH MY GOD I AM BAD AT CONCEPTUALISING PHYSICAL SPACE I DID NOT REALISE HOW BIG FIFTY-FIVE INCHES IS EVEN WHEN ESTIMATING ITS SIZE BASED ON MY EXISTING 40″ TELEVISION I LITERALLY HAD TO REARRANGE MY ENTIRE ROOM AND BUILD NEW FURNITURE TO ACCOMMODATE THIS THING???????
It’s surprisingly thin.
Does CEC and has settings to automatically switch channels based on what just turned on.
Lots of options for controlling and customising various aspects of the television including picture and audio correction, accessibility options including captions and spoken audio transcription (I have not tested the latter feature), and UI skins. You should absolutely poke around the options as much as possible once you get this as there are several options for things like the refresh rate of the display, which I imagine is relevant to a lot of people. (I am not intimately familiar with specifics of refresh rates, but I have seen no tearing or distortion from fast-motion visuals and things appear to animate smoothly.)
Does some advertising for purchasing media through Roku, presumably to offset the cost of the device. It isn’t especially intrusive and only consists of movie posters in a small portion of the screen at very select times in one part of one menu.
Does require a significant amount of opting out of certain things.
Overall a fantastically huge, featureful, and good-looking TV for the cost.

Regarding complaints I’ve seen in other reviews: My product did not show up broken, it has not stopped working despite extensive use since I got it, I have no complaints about the refresh rate, it displays 4k content over HDMI with no issues, they say it’s a glossy screen but it’s really just unusually and disconcertingly smooth and otherwise significantly less glareful and reflective than my previous television, it has effectively no inconsistencies with backlighting or colour (just a small spot that’s slightly brighter, which is only visible at extreme viewing angles or if the screen is effectively displaying nothing but black, and I don’t mean like really dark or a scene at night I mean like literally it is displaying the colour black over 50% of the screen, and only then is it noticeable from a front angle, and just barely at that).

So if you’re one of those folks that buys artisan gold plated audio cables aged seven years in oaken casks, if you buy two of the Ti version of the latest nVidia graphics card because you absolutely need to run everything on “Ultra” at 120FPS in 4k, if you’re the kind of person who thinks Grey Goose tastes better, you probably won’t like this TV.

If 10% not as good as the best thing for 1/4 of the cost is your jam, this is an amazing purchase. I freaking love my new giant TV.

Quite frankly, I was very, very unsure as to whether I should purchase this TV. It is a ridiculously good price, says it has HDR (HDR10), it has some local dimming type qualities and is under $400…It’s also from a manufacturer that, quite frankly, I am not very sure of as I am not familiar. What pushed me over the proverbial “edge” to buy this was two-fold…First, it is quasi suggested by Amazon, the price is great and I know it has a Roku built in. This is the third (I think) generation from TCL and Roku and the first to boast 4K and HDR. There are some outstanding features on this television and a couple cons that I can live with. I’ll outline them below.

I wanted to buy a new TV for my bedroom and the 49” was cheaper than the 43”. Also, in my humble opinion, if you want to get a 4K TV with HDR, it is best experienced with a larger TV screen. I wanted to get the 55” version that has Dolby Vision HDR (because it can use Dolby Vision or HDR10 standards for HDR) but it was cost and size prohibitive.

I saw a LG tv for a similar price but they are still using a RGBW pixel setup for their budget TV’s and it really does not do blacks well nor does it perform well with some contrasting. The reviews, research and data specs I found for this TV all outweighed going with a more familiar brand. Plus, Amazon is awesome and Prime has great benefits to protect us. I mention that as buying a TV online is a bit scary to me as I worry it might arrive broken but this was packed so well it would be malfeasance to arrive broken (or intentional).

After it arrived, I checked to make sure it was in one piece. After I found it was, I set it up. The first thing I noticed is that it weighs less than half a 46” Sony TV from 2010 that it replaced. This thing is LIGHT!! I can pick it up and turn it in my hands by myself without worrying about dropping it. Be careful though.

Concerning Picture:

This has HDR and the colors really “pop” and look outstanding. The version is HDR 10 and the TV has a 10 bit panel. Be weary of TV’s that tout HDR but only have 8 bit panels as they cannot show the full color gamut (aka not really show much of the benefit of HDR). The ones you really have to check are budget Samsung (I love Samsung but the budget ones have some critical reviews; which I urge you to check yourself) and LG. Now, the premier models (aka, flagship) for Samsung and LG are absolutely AMAZING but they also cost a lot more. Nonetheless, the screen is very, very good for the cost and I am thrilled at the price and performance. Setting up HDR is easy but make sure you press the “*” key on the remote for each input to access the settings to change the HDMI setting. It took me a bit to figure that out.

This TV has a refresh rate of 60hz but some internal hardware bumps it up to 120hz but does give it a bit of a “soap opera” effect. Some love it, some loathe it. I am the latter. Either way, in Sports mode it was able to keep up with fast NFL action in 4K and some other programming on Directv (NFL not in 4K but the upscaling was great!). From what I read, I wouldn’t calibrate this TV as it didn’t really help. This is different as calibration usually makes the tv show it’s best picture but that doesn’t seem to be the case here. Oh well, easier for me to setup.

Sound:

The volume gets QUITE loud! What I love about this is an option to use to have “Speech” mode so language in movies, shows, etc, is clearer without having to turn the TV up in general to loud levels. My former TV lacked this. Nice addition. The stock speakers don’t sound “tinney” or bad at all to me. Keep your expectations in check though; this is a budget TV.

Other Features, etc:

SD content and content from streaming is upscaled very well.. That is extremely important, in my opinion, as there is not a ton of 4K material and HDR but it is growing rapidly. Most of the HDR and 4K content out there to stream, you need about 30Mbps download speeds (which rules me out as I can only get DSL). HDR adds another 3Mbps required with 4K.

Breakdown
It has HDR (HDR10 and it looks great for the price)
Great up scaling
Screen cast
Roku remote and User Interface
Simple, fast and easy to use User Interface
Good apps/thousands of channels because it is a Roku

3 HDMI (All can do 60hz 4k at 4:4:4 or 4:2:2)
Headphone/speaker out
OTA Tuner
Component input
Great Sound for a budget TV
1 ARC HDMI
1 MHL HDMI
As wide as my 2010 Sony 46” TV (small bezel on this)
Inexpensive
Full LED backlight array, it seems, with local dimming. It doesn’t perform as well as much more expensive TV’s but it performs well at this price point
Wifi – True Dual Band AC and have had ZERO drop outs thus far

Some cons are:

Needs another HDMI input
No 3D (if that is a con)

Could use more than 1 USB port

I would recommend taking advantage of the 2 year warranty available so you get the 1 year manufacturer one and 2 after that.

Overall, I cannot dispute the value this brings to the table; it’s amazing

I am shocked at the picture quality. I went into this purchase wanting a larger inexpensive TV for the master bedroom. So far I am floored, the picture blows away my Panasonic plasma I purchased several years ago (for 3x the price). The Roku OS is super easy, The antenna integration and USB storage for recording live programming are great.

One small item I can nitpick is the white LED at the bottom center of the TV that remains on after powering off. I haven’t dug through all the settings yet, I will post an update if I can disable it. Update: The LED can be disabled in settings under power settings.

If this set can continue to perform, I will replace my main Panasonic Plasma with the new TCL C Series

The pic is from a nature show “The Hunt” streamed from Netflix.

I can’t imagine a better picture for the price point. That coupled with the Roku OS and I am extremely happy with this purchase