When interviewing with the actual company, I can ask about all sorts of details such as benefits plans, what kind of software they use, vacation schedules, etc... When I'm dealing with a recruiter, I've tried to ask similar questions and get vague responses, or they don't know the answer (they're not the employer, after all). Often, they can't say much more than what's already on the job posting. I'm lucky if they seem to know about the company in more detail than what is already on that company's corporate website.
How should I approach recruiters (in terms of interviewing with them) since it doesn't seem as though I can treat the situation the same way I would with an actual employer? Should I ask questions about their history as a recruiter? Should I ask about the firm they work for? What kind of payout they get for successful recruiting?