Those are certainly great options and should be utilized because you can just list your domains and you don't have to worry about anything else until the sale comes. The downside are commissions, escrow fees, and the fact that you are competing with other domainers.
The title of this thread is "Sites like efty.com?". I would presume this is about creating your own marketplace on your own custom domain.
What we aim to do with
DMP is allow domainers to quickly build their own custom branded marketplaces and point their domains to pages they control. And give them the tools to market their domains professionally. Our adage is "Market Your Domains Like a Pro".
The benefit here is that you can promote your portfolio without having to compete with other domainers. Someone lands on your sales page or landing page and you can promote your other domains, rather than having a 3rd party marketplace promote domains you don't own.
You can take advantage of SEO, social media, and content tools to get more targeted traffic and create buyer confidence. In effect build authority in the naming field for yourself.
You can also build a list of potential buyers when they contact you through the forms on your marketplace and get signals of their potential budget.
Finally, by listing your domains on those marketplaces but having the domains land on your sales pages, you increase the opportunities to directly negotiate with the buyers and/or capture leads. The exception, I think, is BB since they require you to point your domains to their marketplace.
Over the years I have seen many domainers either build spammy-looking sites or start building a portfolio site and then give up. I also have seen a good number of domainers with portfolio sites that were hacked beyond repair. That's why we created
Domain Market Pro and made security a salient feature.