I have used buy-side brokers in a Finder Fee sheme in which I only paid a success fee for an introduction to a company which we ended up acquiring. An open mandate usually doesn't pay off for the broker, so an approach of industry expert brokers or even asking them to contact a list of previously selected companies has worked well for me.

I agree with Alexander and Matthew's points. For a self-funded searcher, there are worthwhile buy-side brokers/advisors out there. I have found some in niche markets that are willing to generate proprietary leads and filter public leads using criteria that we have worked together to create. The nominal monthly fee they charge is well worth the time saved and additional deal-flow, in my humble opinion. My additional advice would be to establish a solid relationship with the broker/advisor before retaining their services. If they are unwilling to invest some time up front in getting to know you and your search, they are probably not the right choice.