My first job was through a recruiter. The pay was low, and the benefits included only a minimal amount of paid vacation time (accrued in chunks, not as a rolling tally!) and a non-matching 401k that was discontinued during my first year (I had to roll over into an IRA). I got laid off after 14 months and eventually learned to know better.
To be clear, that was my best experience with a recruiter. They helped me get my foot in the door at a job related to my major, and as far as I know they didn't do anything unsavory other than make money off of me as unnecessary middlemen.
It took me nearly 2 years out of college to learn not to deal with these people. The following is a list of things that happened to me back when I still entertained opportunities from recruiters:
I'm not really sure what their business model is supposed to be. They try to make it seem like they're offering a service to job seekers, but of course that's nonsense. Used car salesmen do the same thing. They don't seem to be able to match candidates to employees any better than a 2-year-old with access to Google, so that's out. Maybe they are supposed to provide some sort of legal or financial insulation between their clients and the job seekers or to serve as ad hoc HR departments for firms too small for dedicated staff? But even if that's the case, any legitimate demand for recruiters is clearly outstripped by the supply, and they have to result to sneaky tactics to make themselves appear useful.