USA owners. T-mobile or AT&T or other options. Ease of connection

Hey guys. In the US here unless something changes I'm ordering a OPO from the store Friday. I'll pay for the fastest shipping as I will be leaving Boost/Sprints horrible service to either at&t or T-Mobile. I'm just checking to ensure either of these two carriers have no problem hooking up the OPO. I'm a DIYer and rather do my own hookup myself online. Like a year or so ago with Verizon. Where I didn't have to talk to a single human. Everything was done on the pc and a few reboots later everything was a go.

Any experience you guys have had let me know.