Maybe I'm just lucky but I've had great success with my agents.
My first purchase of course I just needed a buyers agent, I wasn't selling anything. Poor thing, I had a huge list of "must haves" and not a lot of money but she worked her butt off to try to find me things. Nothing in the area I wanted was working though, and she suggested a sub division in another town, she swore the condo was exactly what I wanted and for the price point I could afford, if I was willing to give up on the town I wanted. At this point I had nothing to lose, so I went and I LOVED it. It was exactly what I wanted, with the one exception being that it wasn't in the town I really wanted to live in. Even so my work commutte didn't increase at all (I could talke the tollway instead of city streets, took almost the same amount of time door-to-door, go figure).
4 years later I sold, and went with a different realtor (I liked my 1st one but since I was now selling as well as buying, I wanted someone from my immediate area) and she to worked her butt off showing us houses (again, big list of criteria and not a lot of money) and she came through for us. She also sold our condo in 3 days, but that was more due to it being in move-in condition and the hot market in '05. Still, she stayed on top of everthing and even had a back up marketing plan in case our offer fell through (it didn't).
Anyway, buyers agents can still be helpfull, IF you can find a good one. I wouldn't sign a contract if I could avoid it, if I couldn't avoid it I'd ask for a 3 month instead of a six month, if they were just awefull then it's not so long to wait it out.