I'm using ChangeSynergy as well, and I'm really torn. I'm a tester, so most of my interaction with the system centers around the bug database. I also use the ChangeSynergy for revision control on my automated test code, which is always a task fraught with peril. I think a lot of my problems stem from improper training, as I was simply given a login and told to check in my code.
On the other hand, I've found that ChangeSynergy's system for doing complex queries of the bug database simply doesn't work. If you try to match more than one parameter, it always fails to find a match.
I dunno, from a user's standpoint (as opposed to an Administrator or Build Engineer), (Dis)Continuous seems needlessly complex and loaded with bells and whistles that simply won't be used. For my money, I'd rather use a free system that's simple and well-documented (if limited) than an expensive, complex, poorly-documented system that requires special training (available for just a few dollars more, but less important to the company than catering executives' lunches) and a full-time engineer (to be hired any day now, really, we just need to find the right person, no kidding, as soon as we get an open req).
"What do I want? I'm an American. I want more."