I am going to get my college son a smartphone. His Verizon reception is spotty and he often goes outside to get better reception. All of the buildings (dorms, libraries, etc.) have Wifi. He often spends a substantial time on the phone with 2 or 3 people (he dictates papers over the phone). So, I thought a phone with Wifi would be perfect. The Google T1 with the physical keyboard (he prefers and is not really a techy kid) and a nice screen looks very good (and he uses gmail as his primary email). It has Wifi but not UMA. Does that mean that he can make calls on Wifi as long as he doesn't walk out of the dorm (or library) but that they will disconnect if he leaves the building and he'll have to redial on the EDGE or GPRS network?

I have a Blackberry with UMA (on T-Mobile) which enables me to make calls through Wifi (and I also use Google Voice). If I got him a Blackberry, could he make calls on Wifi and then walk from library to dorm without interrupting his call? Are there other advantages of UMA?

I'd say the Blackberry is a good phone (I have the 8320 though it is my fourth Blackberry) but that the G1 would be better for him just in the physical setup.