Well I haven't had much of a chance to play with it but first impressions are good. I literally cannot wait for the jailbreak though - I'm 99% sure I wouldn't buy an iDevice if it wasn't for the jailbreaking.
In response to whoever said that they won't buy one because they don't want to be tied down by iTunes - you aren't obligated to use it at all (aside from initial setup I assume). Once my phone is jailbroken it never sees iTunes again!
I love the new notifications functionality - and the alerts on the lock screen. Siri is also extremely impressive, I've been having lots of fun with it although I do have two issues with it.
- You cannot communicate with Siri without a data connection. For someone who just wants to use Siri for sending text messages for instance, this sucks. Or someone on a slightly limited plan who doesn't want to be charged out their ass to play with their phone.
- It doesn't appear that location services work for the UK (directions etc). It may be a location setting of somekind as I hate the male voice on the UK 4s' so changed Siri to the US English.
More soon - dinner's on the table