I've been reading lots of concerns here and at the carrier site and xda.
A lot of defective units out there?
Honestly, the reviews over at t-mobile seem to have a lot of people giving the S6 low battery life scores because of non-removable battery.
Also, most of the user reviewers don't even have the S6.
Here is a prime example: "No micro SD Memory, No removable battery. Key features that Samsung had. I was waiting for the S6 but without those features I pass. I will wait for the Note 5 and if Samsung. Make the same mistake with the Note 5 I will say bye bye to Samsung and will move to the HTC.
Also, the price of the S6 is too expensive for been a downgrade of the S5.
Cons: memory, expensive, battery"
He gave the phone all 1s and 2s.