Recruiter Pros: they get you through the "referrals"/"network" barrier and hype you up. Sometimes that means 1-3 less interviews. They'll also protect you against shitty companies; most good candidates will job switch every 2 years on avg so there's $$$ in maintaining good relationships on both ends.

Cons: All things equal, companies will favor the candidate who isn't tied to the recruiter.

I'll take one if I don't know the company, but if I know someone working there (and by now, I've met most people), I'd rather opt for someone on the inside. Most of the bigger companies also offer referral bonuses and highly advantage those with an internal recommendation.