The build seems very fast and stable for me thus far. I have noticed one radio issue, though. First, the signal in general seems weaker and tends to fluctuate much more. Additionally, I've noticed that when I lose signals (for instance in the underground metro tunnels) it takes longer for it to rediscover the signal in the stations. Furthermore, there are times when the phone shows signal and a 4g data connection, but I'm unable to make / receive calls, txts, or data. I'm able to fix this by restarting the phone, but it's an annoying issue.