I had a 7280 on AT&T, and recently upgraded to the 7100g (switched over
to Cingular). It is by far the best Blackberry I have used to date.
The bluetooth feature is worth upgrading for, and have had no problems,
except for a couple of random disconnects (not sure if that was the
phone or headset). My opinion is that Cingular has an advantage over
Verizon where I live (northern CT). My wife had verizon for several
years, and got frustrated. It seemed to me that things got worse after
they put in
1xRTT, or at least after we upgraded to
1xRTT phones. Once
we switched to cingular, she has not complained.
I'd recommend blackberry service with cingular. At least in New
England areas, you won't be disappointed.