I received my Galaxy S8 when they were released. I noticed the battery ran down faster than my S7 edge but I chalked it up to being new and trying out the new features. Unfortunately, my 14 day return period was up before I discovered I had problems with my phone. I have AT&T for my carrier and had no problems using them with my S7 edge. I noticed I was only getting one bar sometimes two but never over this when using my phone. If I was talking to people I could hear just fine but the person at the other end said my voice was breaking up when I talked to them. I then took the sim card out of the S8 and put it in my S7 edge and immediately got four bars on my service. I took my phone to AT&T who ran a test on it but did not know why I had this problem but did replace my sim card. This did not help plus in addition my battery drained very quickly and I did not know why. I called Samsung and as suggested did a factory restart to no avail. Samsung then asked me to return the phone for evaluation. I am now using my S7 edge until I receive my phone back from Samsung.