BrandBucket has a great reputation and they do get results. I've sold a few names listed with them. But, they have become as slow as molasses in their response time (up to several months!). If they rest on their laurels a competitor of theirs could gain some market share. I think a nice compromise would be for BB to more quickly make a decision on names, even if it means they accept fewer overall or at least reject names faster that they know aren't going to make the cut. In the end, they do move names so it's still worth using them IMO. The people behind the scenes are great people and helpful as well.
A negative is that names get quickly buried on any of the brandable marketplaces, so it still takes time for the right end user to come along and find the hidden gem (your name) amongst all the others as they won't be seeing your name on the front page above the fold for long. The buyer either has to direct navigate to your domain listing or spend the time sifting through many names.
I think it's smart for a person to try all of the brandable maketplaces (the big 3 of BB, Namerific, and Brandroot) as the types of names they may have an eye for might do better at one venue over another.
Best of luck to everyone in selling their names!