Bought 2 950's from AT&T at launch. I saw the network failure issue from the beginning but was sporadic. However, by the new year it had become daily and sometimes multiple times. I had the device replaced and it went back to like at launch. The slow increase in frequency occurred again and when there was some other hardware issue that showed (wouldn't accept a charge), I had it replaced (around April). My wife's original 950 is just starting to show the increase in network frequency. I definitely am a power user compared to her. I've tried public release, Slow, and Fast preview rings, but none of them have any impact on it. Really annoying to miss important client phone calls and family emergencies because your phone decides to stop being a phone and not tell you about it. I have not found anyone that knows what is causing it (hardware, firmware, OS, network, etc). It can't be too prevalent because not even the AT&T support forums mention it much and people are far less likely to deal with it or figure solutions out on their own.