Exactly what I'm going to do: Hang on to my iPhone 4 on AT&T for now and give the Nexus 4 a tryout on T-Mobile's Monthly4G plan ($30 for 30 days/5GB). I can return the phone to Google if I don't like it and owe nobody anything else. If I like Android 4.2 but not the h/w, I can get an HTC One X+...