Windows Mobile Professional

I'm thinking about getting one of these phones to let me check e-mail, etc. From what I can tell, the HTC/Verizon VX6800 and Sprint Mogul are exactly the same phone. Is there any difference when used with one carrier or the other? Any reason to prefer one over the other (pricing aside, since my company is paying for it).

Also, I was looking at the HTC 5800 with Verizon. The demo in the store would only allow you to view Word, Excel docs, even though it has Windows Mobil 6. Was there something wrong with the demo phone, or can you not also edit these files on the 5800?

Any recommendations on the 5800 vs the 6800? When is one better than the other (I like the size of the 5800, but like the keyboard on the 6800 better.)

Thanks in advance for your help!