Guess I'm going to break my own rules, as there is a degree of (at least arguably) promotion or endorsement implicit in what I'm about to post. However, I've got no skin in this (don't work for Sedo, don't favor brokerage services) and, mostly, I'm posting to describe what or how I think a brokerage service should operate. (Feel free to abuse me if it will make you feel better. ;) and :P)
I don't sell many domains since a) most of my domains are held for eventual development; and, b) most inquiries are . . eh . . misguided? Ill-informed? BS?
When I do sell I don't use brokers.
Over the years I've been contacted by self-proclaimed brokers but not all brokers are up to the game (though some are improving).
For example, IF you want to call yourself a "professional broker" then do NOT convey an offer just because you are asked/instructed to by your "principal". Offers that you (should) know will be deemed a waste of a potential seller's time only undermine the chances that I will ever open another email from you.
Recently I was contacted by Sedo about two "non-essential" domains, one's that were "on the list" for eventual development but not rising up the list ahead of other projects.
The initial offers were lowly but not offensively so. I think I one case I just ignored the first "ping" (Are you interested in selling . . ?) type email or the second email (Buyer offers low $$$$ . . ) email.
In one case Sedo returned a few weeks later with an improved offer. In the other the email exchanges just quickly got down to business.
These weren't big deals but they weren't lunch money. Both mid-$$$$.
What worked for me?
Offer, counter, new offer emails moved back and forth quickly once the ball got rolling. (Since brokers don't get paid unless they "do the deal" I guess they've got reason to keep things moving.)
No issue with buyer covering all costs (I don't need nor did I ask for a broker . . so why should I pay? There was no debate. If there was one . . well . . Ever hear of a deal-killer? :-/)
Domains pushed to Sedo's account @ Moniker so transfers are handled the way I prefer: Push!
When it comes to hunting or doing business I'm a fan of a "clean kill". This was pretty much the case. Again, no "big deal" but, that being the case, all the more reason for wanting to get down to business, get it and get out.
Having never done business via Sedo's brokerage service I didn't know what to expect. Having been through the process I can report that I found their process satisfactory, from start to finish.