1. Your resume, if faxed, mailed, e-mailed, or carrier-pidgeoned to a company, often becomes a millimetric addition to a mountainous stack of paper on some hiring manager's or secretary's desk. Yeah-this is a great way to get noticed! Even though the business of headhunting requires staying on top of the flow of resumes so as not to "snooze and lose" a perfect candidate, recruiters can't help but accumulate piles themselves. Think of how much worse it is in an office with so much more to do than review resumes. I'll say it again: HR and other departments are too busy doing whatever else they do to get around to submitted resumes promptly, even if they ran an ad.
2. Another presentation benefit in being represented by a recruiter to a hiring company: you get heard about rather than only seen in impersonal black and white. There's a lot to be said for the sensory dynamics of hearing about someone and picturing them in your mind rather than sorting through descriptive words. There is room for personality, humor, casual friendliness - LIFE - to color the feeling that a hiring manager gets about a candidate in a verbal presentation that simply cannot be conveyed in the cold, hard world of ink and 201b. bond. The "life" that the hiring manager feels is, for the most part, that of the headhunter. However, if the headhunter is a trusted, respected advisor to this company, that surrogate life can attach nuances of feeling to the candidate in the employer's mind.
Obviously, it is important here to emphasize feeling. In many years of recruiting, I have grown keenly aware that, fitting within a certain range of qualifications for a particular position, hiring decisions many often come down to 90% chemistry and feelings. So, the earlier in the hiring process that certain attractive feelings can be attached to a candidate, the greater the chance of an interview, if not eventual hire. A good recruiter attaches those feelings when presenting you to a company.
3. There is a financial security benefit to being placed by a headhunter. Rest assured that a company willing and able to pay big money to a recruiter to hire you is a financially viable organization. You will find that companies with the savvy to utilize search services usually offer more attractive compensation and overall "packages."
4. There is an insurance benefit to being placed. Think about it: if they pay big bucks to hire you, how committed do you think they are to your working out? Having made an investment in you, they now have a tangible commitment to your success - more than to a person who wandered in off the street. Their effort to ensure your success is definitely colored by their not wanting to waste money. Sure, there's usually a window of time, a guarantee period, in which they could cut a candidate loose without incurring too great a loss. However, with all the legalities and other matters involved in the hiring/firing process, a company would seldom use this loophole as a "try them out" process- it just is not worth it. When they hire you, they want you to make it. They're banking on your success.