Love mine, screen is phenomenal, so clear compared to 3G/3GS, camera is so much better, hd video is great. Performance is outstanding too. Design is so high end compared to the toy like appearance of previous generations too. The glass looks lovely on the front and rear. Phone calls are great with the noise cancellation too.
Agree, iOS4 on a 3GS is still a damn good phone. However, the iPhone 4 has jumped it to a whole other notch in my opinion.