I think my biggest complaint about CBBA was that their agents seem to constantly push the services that CBBA provides or gets commissions for. When buying, they made sure I used their escrow company, tried to push their lender as hard as possible, got their recommended home inspector in, got a home warantee through their partner... the list goes on and on. I'm sure this is common, but I still didn't appreciate it.
The other thing is it felt that I was doing most of the work. I was monitoring listings and finding places before my agent would -- and in a quick selling market, a few hours does matter (in fact, the first home I wanted to put an offer sold minutes before ours was sent in).
Other agents I talked to while looking (at open houses, etc) seemed much more personable and interested in helping.