I have 2 Lumia 640's and 1 Lumia 640XL in my household coming up on two years now. All on T-Mobile. Living in Utah, I have had very few issues that people often complain about here in the forums. So last month we went on vacation to southern California and all three phones were unbearable to use. The maps app in particular would constantly drop satellite connection, freeze, restart, crash on all three phones. Often we didn't realize it until we had passed our exit. From Newport beach to Santa Monica my wife was fighting all three phones to keep the maps going to get us there. There were 9 drops on my phone in just the last 6 miles resulting in 3 u-turns and lots of frustration. My daughter's phone never found a satellite that whole day. It would always take us 3-4 miles just to get the turn by turn directions going. Other apps also struggled. Cortana often couldn't connect at all. The web browser was painfully slow. It was so bad, that if I had to deal with that on a daily basis I would have switched to android long ago. Back in Utah, everything works near flawlessly again. Has anyone else noticed or experienced this on a vacation? Is T-Mobile that bad in southern California? If it is the network, would we have had the same issues on a droid or IPhone?