UMA wasn't as glamorous for me as some of you are telling. I'm glad you had good experiences but mine was pretty poor. The quality was not as good as going straight to tower, multiple drops on a very low traffic network and occasional bad static. Also I was never able to successfully switch from WiFI to Tower or vice-versa. They still have work to do with this as the technology I don't feel is polished yet. The concept however is fantastic. I was able to use it in Europe extensively to send texts for work. I was using a Curve 8320. I've since switch to an e71 and use Google Voice with Gizmo5 and works well.

Also have you noticed that there is no UMA in any of the 3G enabled phones (G1, MyTouch?). I don't have verification on this but a guy at the T-Mobile store told me the 3G and UMA functionalities conflict. Anyone else hear this?