Let the hive mind of Engadget get that for you.
"I just switched to Sprint from Verizon about three months ago for the Pre. Then I went for the Hero about a week ago. Now, I miss my hardware keyboard and am thinking about switching to the Moment. I am still able to switch back to Verizon if I want and get the Droid when it arrives. Should I just trade up to the Moment when it comes out, see if I like it, and if not switch to the Droid? Or something else entirely? Help!"
I am currently on Cingular's SmartPhone Connect Unlimited w/Xpress Mail unlimited data plan. $19.99 monthly.
BTW, Cingular network settings are "forward compatable". I am using a HTC Tytn on it and enjoying full 3G UMTS speed. Take that EV-DO. ;)