I went from sprint to att and a nokia 6820 and still was itching for a BB so i dumped that and went to TMO. I haven't looked back since. I use it for both and really have no problem with its size. It's as slim or slimmer than 95% of phone out there and the width doesn't bother me. It's very pocketable IMO.
Miss the bluetooth and speaker of the nokia but I'm getting by just fine :D