I'm debating whether or not to buy an unlocked iPhone off craigslist that have been updated to the iPhone 4 OS - I hear that the new one isn't compatible with T-Mobile and such. Is this true? Detailed opinions and feedback very much welcome.
I'm looking for it to work on the iPhone 3GS specifically. And I know T-Mobile has great options I could go with, but I have the first generation iPhone and I love it, I'm just looking for an upgrade.