I use a stop bath, and my reasons are pretty much covered by Bob's post on page one.

I'm not worried so much about the continuation of development while in the water bath. I am however, quite careful with my stop, as I use the (obsolete, yes I know) kodak powder fixer in the nice yellow/orange envelope, and it has limited capacity, and needs to be treated gently. An acid stop allows me to do this, and since I develop with the (yes I know, no imagination) divided D-76, I don't have any problems with pinholes as I might with any of the very exotic developers.