I've had the Z3 for a good few months now, and as anyone who knows me will testify, I am incredibly hard to please when it comes to phone, but I have to say, the Z3 must be one of the most underrated phones out right now. It seems to be largely ignored by almost everyone. Its not neccesarily the best in any one area but as an all rounder it really is very difficult to beat.
Example, only a Full HD screen, yes, but its bright, vibrant, plenty sharp and is actually usable outdoors (my old M8 was pathetic compared to the Z3 for outdoor use). Also, it means that the battery life is much better than some of its rivals.
20 Megapixel camera is among the highest found on an android, and leads to incredibly detailed photos, which generally come out well. I do find the lack of HDR somewhat confusing though, not to mention the lack of OIS, but generally it doesn't seem to matter.
It feels very premium and well made, as good or better than an iPhone IMO.
Sound from the speakers up there with the M8 (which has excellent speakers).
The Operating System feels almost as good and responsive as a Nexus, I've just installed all of the Google apps and replaced / disabled the Sony ones.
Battery life is excellent, 6 - 7 hours SOT possible. 2 days light use.
Awesomely impressed, everyone talks about other phones but these really are great. I chose it over a Galaxy S5 / Note 4. I had a One Plus One before and this is much more polished and responsive.
Downsides are the headphone out is a bit quiet, shame you can't default to 20 MPX using the shutter key, slow updates, double-tap to wake in combination with smart lock leads to phone unlocking in pocket on its own.
Never had the bottle to dunk it, especially after reading posts on here saying theirs died, but its nice to know it'd survive a bit of rain or a quick drop into a puddle or toilet. Case is a must I reckon, it would shatter if dropped.