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!"
Damn shame this isn't running; conceptually it looks absolutely fantastic and it would overcome all those annoying gimmicky solutions, such as Nokia's twist phone, and it would allow for different preferences in terms of the actual layout of key pads etc. potentially.
Only problem is if you have sweaty hands ...