I’m an iPhone 3G owner, and am pleased that my “nearly obsolete” two year old iDevice qualifies for the iOS4 upgrade. I understand (and am satisfied with) the trade-offs Apple made to minimize the performance hit on this model, but as others have reported I’ve noticed a distinct slowdown in my iPhone since upgrading. Apps take longer to load, Mail messages open slower, the whole system just feels more sluggish.
A comment posted to MacInTouch suggests that a double Hard Reset of the phone may help minimize this problem, and indeed this has noticeably seemed to help with mine.

