I'm a long time Windows mobile user, who decided it was time to make the move to Windows Phone 7.
The good bits:
+ The OS is beautiful. Very responsive touch screen, and a pleasure to use. You really can't stop touching and playing with it for the first few weeks.
+ The phone itself looks great, very solid and a nice size.
+ Facebook, linkedin, Windows live, etc integration with your contacts list is amazing. All information from each contact in one place.
+ Live tiles are great, so you know at a glance if you have any missed calls, unread emails, messages, or outstanding tasks etc
+ The software keyboard is actually very good. I've always gone for the hardware keyboard option, but there wasn't one available when I got this phone. I've found my typing speed, especially when you tilt the phone into landscape, is just as fast as with a hardware keyboard.
+ The phone starts up from being switched off very quickly (less than 30 seconds before it's ready to use).
The bad bits:
- The camera takes great pictures, although it takes a bit of skill to execute. You have to half press the camera button to auto-focus, this takes about a second, then you fully press the button to take the picture. This can be a bit tricky if you are in a rush to take the picture.
- Far fewer features on this phone that there were on my old Windows Mobile phone. E.g. no internet tethering to pc, copy/paste, and it feels less customisable, e.g. you cannot add your own ringtone. There's also no turn by turn navigation software available at the moment.
Another point to note is that the charger is a micro USB connection (like the amazon kindle). Not the same as the mini USB connection that came with all my previous HTC phones.
Gave it 5 stars although I feel there is still a bit more to come in the future with updates and new applications to fill in some of the missing OS features. Overall though, I'm very happy with this phone and would definitely recommend it. It looks like Microsoft have taken a couple of steps back so that they can go 10 steps forward. But regardless of what is coming in the future, right now this is still a great phone.