One thing you do have to look out for is that recruiters get paid after a period of employment (3-6 months in my experience). So that can create a perverse incentive to fire someone you’re on the fence about. This really shouldn’t happen unless you’re working for an extremely cash-strapped place though.
All of the applicants he brought were better, than the ones that applied via an online job portal. Even tough some ask 20%-40% over our budget, we are still considering them.
I am conscious of which roles I offer to outside agencies, but once I do, I stop worrying about the cost and focus only on the value I can get from the candidate. Those agency roles are some of the most competitive positions; I don’t expect to be able to hire the best who happen to not realize that $0.75x is smaller than $1.00x for positive values of x.