I've closed a number of domain sale deals after being contacted by domain name buyer-brokers or agents.
What I've liked about the process thus far is that they grasp the variables that affect a domain's market value. Also, I appreciate the fact that most "get me", as in they know and/or respect that I know a bit about the business, that I'm a professional (legal AND domain), that I'm pretty cut-and-dry in my negotiations, and that I don't need their client's money. Grasping that simplifies things for everyone.
Since these are not sales I have in any way solicited AND I like to "keep things simple" I routinely communicate a firm/final "net to me" price, which effectively requires the buyer to cover all brokerage and escrow fees. The less we have to talk about or negotiate the more likely a deal will close.
Unfortunately, even brokers sometimes present low initial offers. I find such offers mildly vexing but I'm usually inclined to give the better brokers the benefit of the doubt, assuming they're working on instructions from clients.
Poorly educated/trained "~staff brokers" - really nothing more than customer service reps working for certain entities - are NOT worth the time. Offers that arrive based upon automated domain appraisal systems continue to suck, make me laugh, etc.
My advice, if you're in the hunt for big domain-game, is to consider using an EXPERIENCED brokerage.
Anyone else have any experience on the sell or buy side with domain brokers?