I've been on the job market the last few weeks, going mostly through New York recruiters. The quality of the experience has varied wildly, with some obviously doing the minimum work necessary, and just as obviously not knowing or caring about the "acronyms" on my resume. Others seem pretty professional, have apparently done research, and the clients they recruit for would indicate they have a reputation to maintain.
In the end, the gross factor doesn't really matter to me -- the recruiters find me on LinkedIn, and I just say "sure, I'll talk to XYZ Co." unless it's obviously sleazy or a bad fit.
It's a bit grueling to cast such a wide net, and it's obviously a hustle, but for me it's mostly just a way to get an initial phone introduction/screen with companies, and from there it's apparent whether it's worth the trouble to move to the next step.
I might not go this route again, though, having seen how little most recruiters add to the process.