Firstly credit where its due, this is a fantastic idea, and well done Sony for bringing the idea to market. If they got this right, this has the potential to be massive especially at this price point.
The hardware is in my opinion very well made, and actually looks good. The screen is okay and functional and the buttons feel solid. Can't complain on the hardware side other than battery life which is average at best (6-8 hours). Not great if you are using it as a watch!!
The software is quite frankly a disgrace. Its like they came up with the idea, got vey excited about it and then couldn't be bothered to finish it! To be quite honest when it actually works its pretty good, but this is a rarity. I agree with other reviews regarding connection problems. I use the HTC Desire HD and have to (try) and reconnect regularly. Very annoying.
The frustrating thing is that its such a cool gadget, and I really wanted this to work. I will be holding onto mine to see if it improves with updates over time, but it will most probably stay in my drawer until this time comes. In the mean time another company should step in, copy this idea, make it work and make a killing (HTC please are you listening), Sony will be kicking themselves.
I give this a generous 3 stars for the innovation and the potential, would love to come back and update with some positive news after updates. If your a gadget obsessive like me buy one to play with, otherwise forget it