As a candidate, notably one without full-fledged production experience, my experience has been that external recruiters are completely useless, particularly to newer devs. I have two main problems with them:
1) As Michael says above, recruiters lack the technical expertise to evaluate candidates. The most forthcoming recruiters I talked to in the past said "We think companies will see you as a junior, so we can't do anything for you." John Sonmez said in The Complete Software Developer's Career Guide that the best argument for recruiters is that they can do a better job than you can making an argument to employers as to why you're an attractive candidate. I have seen nothing in reality that supports this.
2) This problem goes all the way from juniors to seniors: That commission cuts into YOUR bottom line, making you arbitrarily more expensive. Devs have to be good at so many things now, it's not really that much more work to brush up on your inbound marketing skills.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.