There are some positives, and a few big negatives comparing the Z4 to its predecessors.

Positives: Loved Android 9 (“Pie”) which was installed out of the box, no upgrade needed. Battery life was a huge improvement. With my heavily used device (multiple GPS apps, bluetooth, lots of long calls) my Z3 Play without a battery back would last about 5-8 hours before I would need to slap a battery mod onto it; but the Z4 would go all day and I never need to add a battery mod as long as I can get it to a charger by sleep time. The 1080p screen is gorgeous and much easier to read in sunlight versus the Z3 Play. All around, the device is much faster, snappier and apps work better. Love that this has 128GB out of the box storage. The built in camera is excellent with 48 megapixels and a high quality sensor – night mode actually works. The camera software is also much improved with additional filter features for social media integration.

Negatives: The screen while excellent is much more fragile than the Z3, Z2 or Z. My Z4 is already in the shop for a screen repair after a very short (2 foot) drop to a tile floor that killed the entire screen. All of my other Z phones survived much, much worse than that on multiple occasions. The moto mods do not fit flush to the phone due to a slightly curved beveled edge that the Z4 has; an aesthetic issue only but it really might bother some folks. The 360 camera is not very useful because poor software makes it limited (especially when it comes to editing which is a critical part of the 360 camera experience). The on-screen fingerprint sensor is extremely sensitive to movement, finger placement, angle and cleanliness of screen and finger. Many times it just doesn’t work or requires multiple unlock attempts. This is a problem with all on-screen fingerprint readers I think, and I would much prefer to go back to the separate reader.

-update after having this phone for a couple weeks. There has already been two OTA updates. The finger print scanner has improved considerably. Either it was the update or there is some machine learning going on here.

Other things I’ve noticed. The back of this phone has almost like a matte surface finish. It seems to provide a lot more grip than my old Zplay. I don’t drop this phone nearly as much.

The power button has a much more noticeable tactile feel and audible click.

One small complaint is calls. To me it’s very picky about speaker alignment near your ear. People can be hard to hear sometimes if it’s not perfectly aligned…. Or I’m going deaf.