My phone works fine with WIFI, but when I go out of the house, my phone starts to get hot, while the screen is off, and the battery drains down rapidly. I have upgraded to 215 and re-calibrated the battery and done a factory data refresh, but still no joy. I am almost certain that the cause is the 4g radio or the sofware that uses it, especially when the 4g signal goes in and out. The only solution I have found, is to set up a smart action to turn off cellular data when the screen is off. I can easily go all day and night with moderate usage, when this smart action enabled. I believe that all the 4g phones that have come out before the razr have had similar problems. Verizon should have addressed this problem before aggressively pushing their 4g network. The average customer would most likely not be comfortable programming smart actions. Just my opinion.