I upgraded my wife's iPhone 3GS to iOS 5.0.1 and now basic tasks like opening apps like Texts/Phone dialer are now slower than before. I understand the 3GS is 2 years old, but just being able to type Text messages fluidly is a super basic task that a 600Mhz processor should handle just fine (as it did on iOS 4.x and 3.x). If not, Apple shouldn't be pushing and advertising iOS 5.x for 3GS's.
Anyway, what iOS version do you recommend I revert to?
Although the iPhone is no longer jailbroken, I recall backing up the "SHSH blobs" to Cydia when it was jailbroken. So I should be able to revert to builds no longer signed by Apple.