"much bigger change" than what happened during the Sony Z series and when they introduced the X series just recently to a resounding "meh". Sony has kept to their "omni-balance" design for the best part of 5 years I think and were getting criticism for it stagnating.

This seems to be an aluminium oblong "tube" extrusion with end caps and a screen with curved edges. It's being compared to the N9 and Lumia design on the Sony blogs and there's certainly a touch of that. I do wish they'd reduce the top and bottom bezels a bit though.

It's a candidate for my next phone certainly as I like my Sony phones (since the UIQ days even) although I'll hang out for a compact version. Currently I've got a perfectly functional Z1 compact and I was pondering a Z5 compact instead of the newer X series until this came along.