Not trying to sell myself as an expert but I have sold a LOT of books. My thoughts on the best places to sell:
1: CGC Boards - I have cleared 5-10% profit in books sold here. I also get the enjoyment of knowing the people buying the books and making long-term relationships with folks on the boards. Only con is that some of you lot are a bit squirrelly and you have to deal with folks not paying promptly. You also have to do your own shipping.
2a. Heritage - Definitely the way to go for high end GA books with an older clientele. Some old farts don’t like CLink’s format and don’t like to stay up late to bid frantically at the last minute to win a book. The Signature auctions give you a fairly accurate assessment of the value of your book. Barry Sandoval is top notch and their catalogs are awesome if you want to look back on books you’ve sold in the past. High-grade SA and BA books might get lost in the volume of books offered in their Sunday night auctions. My results are typically a 0-10% loss after BP.
2b. CLink - The place to go for High-grade SA and BA. The last-second bidding wars can lead to some truly outrageous results. Hard to say if there is money left on the table due to the lack of one-on-one bidding. Josh Nathanson is top-notch and pays attention to his clients. My perception is that high-grade and pedigreed GA books don’t do as well on the site, maybe due to old farts not wanting to stay up late to bid on books. Some of my BA and modern books got killed here. My results are usually a 0-10% loss after commission.
3. Everyone else. I’ve never sold in eBay and did not enjoy my experience on CC. I never tried anyone else as CLink and Heritage seemed to provide everything I needed.
I should add that I sold my Avengers set through Metro and made an excellent profit, mostly due to my Avengers 1. I’ve not always been a fan of the folks at Metro but they did fine by me in that deal. None of those books have ever shown up on the market since and I was led to believe one of the Avengers cast bought the lot. The lot was over 500 issues with 475 being highest graded copies.