I'm just going to rock the case that comes with it until hopefully more case options come out.
T-Mobile is selling the Tech21 case in store. I've had it on my last 3 phones. It's light, thin and provides great drop protection.
Which one of the Tech21 cases did you pick up? The clear on, or the slim green "pine"?
The case that comes with the 7t provides decent protection and looks good with the colors of the phone. Clear cases tend to discolor after a bit of time though.