I've had 3 friends in the same situation as me (renting out a second house), so I recommended Renters Warehouse, and everybody's had great things to say and great experiences. It's just one of those situations where there's nothing but good things to say.

Their speed as far as placing tenants has been right -- if they say it'll be 2-3 weeks, then it'll be 2-3 weeks. You also get the best deal on their pricing, and the quality of the tenants they find is extremely high, which is the most important thing when you're renting out your house. It was a phenomenal experience.