I have brandable com names at both Squadhelp and Alter. I sold more domains on Squadhelp from a smaller portfolio.
Squadhelp displays that 95% of the traffic to my domain names is Squadhelp-influenced, meaning that this traffic is the result of the Squadhelp marketing. Only 5% is type-in traffic.
At Alter, 16% is the marketplace traffic, 3% is from the partners (Dan/Sedo), and 81% is type-in traffic. But I sold less domains at Alter from a larger portfolio. These are mainly two-word brandable .com names. My Alter names were manually appraised and approved by Alter before, so these are good names.
Squadhelp charges 30% commission (there is less commission if the name is expensive), Alter charged 10%.
I think the conclusion here is that you need a lot of traffic and eyeballs to these brandable names to sell them. 10% commission is not enough to drive enough traffic.
So I will transfer my Alter portfolio to Squadhelp and from now on I won't complain about the 30% commission

Looks like the high commission is mandatory to drive enough traffic.
I also considered BrandBucket, but I think SH has more visitors and SH performs more agressive marketing and they are more innovative.
I don't like BrandPa or Namerific.
Daaz/Dan: sure they charge low commission, but they don't do the necessary agressive marketing like SH does.
Of course I will list all my Squadhelp domains at Afternic Fast Transfer, and enable the Sedo syndication for all domains.