I've run my Storm 9530 on Verizon since the beginning and I love it.
However, if you want a touch screen device on TMO, your best bet is an unlocked iPhone. My friend runs his on TMO and it's much cheaper in comparison to the Storm / Black services costs. Additionally, if you work in any of the science fields, there is a plethora of amazing apps available for the iPhone that make life wonderful.
For example, when studying any intricate organ such as the brain or heart, there are apps that allow layered saggital and transverse inspections. This is amazing. I will find it very difficult not to cross over if the iPhone ever comes to Verizon.