Recruiters can be rubbish, but they can be good too - same applies to every industry, whether you're an IT salesman or an IFA.
What most people fail to grasp is the dynamic of a recruiter. They don't work for the candidate, they work exclusively for the client. If the candidate was to give the recruiter a wedge of his salary then I'm sure the recruiter would work for them. The majority of people seem the think recruiters are there to find them a job... not the case I'm afraid!
People tend to get on their high horse and renounce recruiters as scum or slimeballs, and then need to turn to them to find themselves a new job... and then go back to renouncing them...