I've had the same cell service for 14 years. It's gone through company after company and obviously is no ATT.
The iPhone is invaluable to my business due to the MobileMe feature that keeps all of our accounts and client appointments synced over the air. I can literally put info into Bonnies phone like phone numbers and appointments without her being there. Wherever she is I can add data to her phone. Priceless to me.
Gives us the freedom to conduct business without locking us to a location.
All of our data is backed up at all times this way through Apple.