7135 / Treo reception?

Hi all.

Is there anyone who's had a Kyocera 7135 and then replaced it with a
Treo (650 / 700p)? My 3+ year old 7135 is still going strong, but
I've never had good reception at my office. I'm thinking of replacing
it with a new Palm Treo but not sure if I also need to dump Verizon.
Do the Treos get better reception? Should I jump to Cingular/ATT and
a new Treo 680/750? Changing companies would be a pain since I've got
a family plan with two other phones on it.

Thanks for any info.

David