The free T-Mobile SMS service does not work. Didn't expect it to as the SIM IMSI would not be one belonging to TMo.

However, once on Gogo, all services work and I mean all services. On a whim, I dialied my wife and the call went through. She was a bit surprised knowing I was in the air. We usually communicate via Apple iMessage. Call was crystal clear without any stuttering. Won't do it again as I hate being "that guy." SMS and MMS to and from my wife also went through without any issues.