DON'T DO IT!!!
It's identical to the T-Mobile MDA. The T-Mobile MDA, Cingular 8125, Sprint something-something are all rebranded versions of the HTC Wizard. BUGGY AS H-E-DOUBLE-HOCKEY-STICKS. The processor is super slow, it had trouble answering phone calls in time when I was doing more than one thing at a time. AIM support is virtually non-existant due to Windows Mobile 5's inability to keep programs running while the phone is in "standby" mode. Anyways, I had the worst time with the MDA, and I gave it a good couple of months before I tossed it.
BTW, I am qualified to make these remarks. I went to the MDA from the Treo 650 because I wanted the bigger screen and the WiFi. Biggest mistake I ever made. I wish I had the money to go BACK to the Treo 650. AIM support on that was at least there, albeit sketchy.
I ended up going with the Sidekick III when it finally came out, so I could get AIM support back. I highly recommend one of the Sidekick line if you are looking purely for AIM support and size of keyboard. I am missing the touchscreen a little bit, but I am definitely getting over it. The Treo and MDAs were cool for their "look what I can do" factor as far as movie playing and games for a while, but the novelty quickly ran out.
Bottom line: DON'T get the MDA, Cingular 8125, or any other re-branded HTC Wizard device.