I have this phone on Orange and its absoultely fantastic, I love it to bits! If you are worried about the battery life, you can easily tell the phone not to use 3G and it can be used as a "normal" GPRS phone.
The camera is brill, video calling works a treat, bluetooth and organiser functions all very useeful.
The only small niggle I have is that when bluetooth is switched on, to receive data from other phones or to be shown as "visible" the handset flip must be open, but thats a small price to pay for an exceptional handset!