What BB9900 phone of the four listed is the best on carrier - AT&T?

Here are the four radios ( phones): RDE71UW, RDE72UW, RDY71UW, RDY72UW.

I recently moved my service there and my phone is destined to EDGE ( T-Mobile version)

Thanks for you help!

They are all UMTS 850, 1900 compatible, so any one should work. If you can, make sure before you buy that you see UMTS 850 (or band 5) and UMTS 1900 (or band 2) listed.