Ok, after almost a month owning and heavily using this phone:
Pros - stunning design, very fast performance, excellent waterproof ability, great call quality, great camera (important to me as a keen amateur photographer) with plenty of manual control, beautiful screen (excellent for watching movies and photo viewing), surprisingly robust considering the elegant design.
Cons - poor loud speakers, Sony UI is a bit dull, volume rocker is a touch small, absolute fingerprint magnet (mine is the all black model), some annoying and unremovable bloat ware.
I was worried about this phone being a bit fragile when I first got it as it's wafer thin,almost all glass construction suggests but I've now dropped it twice from about 4 ft and it's just got a tiny scratch in one of the corners on the aluminium part of the frame.
Haven't used the galaxy s5 or any iPhone but the Z2's design and aesthetics leave the plastic Samsung and boring apple phones for dead in my opinion.
Hands down, the best smart phone I've ever owned.