I learned a long time ago to buy unbranded/unlocked phones. I prefer phones unbranded because I hate all the garbage a carrier will load on your phone. I need my phones unlocked since my wife is French, so we go to France a couple of times every year.
When I was a Palm enthusiast, it was never a problem getting an unbranded/unlocked phone. After HP purchased Palm, I moved to Nokia and it was never a problem getting an unbranded/unlocked Symbian OS phone.
Now it's getting more difficult to find unbranded/unlocked phones in the states. I was going to get a Lumia 920 this last Spring, but AT&T still wasn't unlocking them due to their exclusive deal. I was thinking of getting a Nokia 2520 tablet, but it's the same issue, they come locked.