Total BS. My 3GS runs iOS4 just fine ...
Mine does too but it doesn’t use all the functionality features that iOS4 has but does use them all on the new iPhone4.
Same goes for the 3G but with even less features than the 3GS can use. Except for the redone mail, I see no reason to upgrade from a 3G down ... to iOS4, do you?
The issue isn’t with the 3GS it’s with the 3G. My daughter and I had similar phones (she has since gotten a new one because hers was so frustrating after the ‘upgrade’ to 4.0) and I can tell you this is not BS.
My iphone has not run well since the upgrade and 4.1 was only a minor improvement. It has been a major irritation and what I considered a great phone has been rendered agonizing slow, requiring multiple daily reboots to get apps to run.
I would not upgrade if I had to do it over.