Count me among the users who've seen data connectivity issues reappear after updating from 10.0.3 to 10.1. I'm outside the United States at the moment, using a non-Verizon SIM, and since the update a lot of the same problems (albeit not quite as severe) have returned. It's frustrating because for the first part of my stay abroad, I was running 10.0.3 and had no problems at all. Now, with 10.1, we're back to data dropping down to 3G in areas where other iPhone users stay connected to 4G the entire time, losing the GPS for no apparent reason, etc., etc. I'm fairly convinced at this point that Apple just released a crappy phone and hasn't a clue how to properly troubleshoot it.