Bad news about "bad sound quality on T-M iphone 5s" from MacRumor forum. Here is the description of the issue: " I switched to an iPhone 5S on T-Mobile from a 4S on Verizon. The sound quality is terrible. It is very tinny and sharp, with almost no bass and too much high frequencies. It also sounds slightly distorted at times. It's so bad that it actually hurts in my ears when I use it with the white Apple headset, so I have to turn the volume way down. I did not have this issue with my 4S on Verizon."... There are more info in that thread. Seems to be a warning to me for holding a bit longer for their service. Kind of disappointing and frustrating now just a day b4 receiving my new 5s ...