My wife's iPhone 4 told her an update was available. After reading ArsTechnica's review, I told her to not install it unless she wants her phone slower that it already is.
Yeah, I would wait as long as possible... until they hold a gun to your head.
I waited a real long time before upgrading my iPod Touch to iOS 6. I swear it ran faster under iOS 5. I like the new podcatcher, but other than that there's nothing I care about.
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“The Government of Spain will not applaud those who set the world on fire just because they show up with a bucket.” - Prime Minister of Spain, Pedro Sánchez