I was hoping to get some unbiased opinions from an unofficial community as oppose to the Apple forums where the only people who sign up are people with problems. I've just clicked cancel every time iTunes pops up to update so I'm still on 3.1.3 on my iPhone 3Gs. I've been avoiding upgrading to iOS 4 because all I've read are horror stories but admittedly mostly from the Apple forums. My phone isn't jailbroken, I use it on Rogers in Canada. Obviously I'm wondering if all this talk about worse battery life is true and if so, how bad? How widespread are the issues with apps crashing and the phone rebooting during calls? Is this just an Apple forums thing making the problem seem worse than it is? How is the performance on the 3Gs and are the performance optimizations for the 3G in 4.1 also noticeable on the 3Gs? Another issue I've seen is that iOS 4 causes problems with the USB connection on some car stereo decks. This is the main thing causing me to avoid upgrading. I've specifically seen my JVC KD-R600 mentioned. Has anyone had trouble using their iPhones with their car stereos? Call me paranoid but with there being no way to downgrade back without voiding my warranty, I want to be sure my phone isn't going to turn into a POS with 2 years left on my service contract.