isn't it the same as the xperia z though.
Of course not. Just installed it, messing about a bit now. It's ultra smooth, better than CM10 on my Sensation. Dolphin is super awesome on it as well, and the stock browser is nicely optimised.
I also love that Sony don't restrict which apps you can disable. Since it's for my dad I disabled Facebook, G+ and deleted Twitter.
The screen is astoundingly good, definitely the best I have seen outside of Xperia ZL and the HTC One. Amazing quality, didn't expect anything like this for a mid-range device for £150.
The build quality is passable, it definitely feels more expensive than it is, but it's not great. I don't expect more than this though given the price.
The size is amazing though, a high end phone of this size would be a killer device for whichever company releases it. It's about the same size as the iPhone 5 (nor surprising given that it has the same sized screen.
All in all, it's a great phone, and for £150, there is nothing else like it on the market that is as stylish and has as good a screen. I have no idea why it was getting such poor reviews earlier when it was released, maybe the 4.1.2 update makes it more usable, but I think it's just review sites having some bugbear about phones with shit specs (even though the price reflects those low specs).