I'm having issues where every 36-48 hours it stops connecting to any cellular signal, and refuses to "search" for cellular providers/signals. A restart of phone fixes it and without moving a foot I suddenly have full 5 bars of signal. I also can not get it to connect to LTE in areas where I know T-Mobile already has LTE. I believe these issues are related, hopefully replacing the SIM will fix them which im going to try tomorrow. The SIM was one I got at the T-Mobile store in febuary when I bought a Verizon htc 8x to tide me over until a new wp8 release on t-mobile. Although it maybe related to wifi calling which I tend to be on 50% of the day as both of my jobs have no cellular signal inside. I will also try the "airplane mode" fix, but if I have to do that every 2 days, I don't that much of a solution.
I also had one instance of a sent picture message only transmiting half the image, might also be sim card related.
Reception was pretty bad the first few days I had the phone, and has since improved significantly. I think what other people have mentioned , that it has multiple antennas which it can select (for each section of aluminum around the phone) is related to the problem, perhaps if you start a call one way and then change your grip? Although ive never had reception issues during a call.
Other then that the build quality is excellent on mine , and phone runs great. Although once when I turned glance screen to "peek"
mode I got the error where part of the screen is black and part is showing what you are expecting to get. So perhaps for the people with that issue they should turn glance off or to timed.