The recruiting process is always faster with a professional recruiter. The professional is 'race-ready' and will take the checkered flag many laps ahead of an in-house recruiter who was slow to get up to speed. Remember—they've spent their time at the track, learning the river and traveling the world of employment.
Additionally, the ability to locate a person who is able to 'hit the ground running' is paramount. Consider the impact of hiring someone through less effective sources then having to invest additional time and money on training and orientation—probably an amount in excess of using a professional recruiter in the first place.
It is imperative to consider the profit opportunity and competitive advantage lost each day, week or month a position remains vacant—or tended to, at best, in an ineffective manner.