Headhunters

Would you use them or not?  In the academic world, headhunters (or recruiters not based at the hiring company) are never used (to my knowledge), and most of the ads for tenure-track jobs specifically state that recruiters are not welcome.  During my non-academic search, quite a few career advice sites recommend using headhunters, and some suggest using more than one at the same time.  Unfortunately, it seems the advice to take on a recruiter often stems directly from a quasi-interview with someone employed or attached to the recruiting firm, and consequently I find their direction must be biased.  Coming from the academic world, I am leery to try out these recruiters, and I don't know if, given that everything about my leaving academia is supposed to be sort of 'hush-hush', I want my credentials (or lack thereof) to become mass-distributed such that I am labeled a hopeless, saturated case on the job market.  I guess I really don't quite understand the entire process, so I suppose I am a bit ignorant.  Anyway, as I received the 35th job rejection last week, I am starting to get concerned - I can't even get to step 1 of the selection process! (an interview, even a phone interview would be great).  What are your current thoughts about using these agencies?