I've only seen Glyde mentioned in the forums but I've yet to check it out until today. I signed up and I'll try selling some things on it just to see how it goes, though as others have said, selling anything below $10 seems ridiculous considering the 12% that Glyde takes.
I know it doesn't make sense business-wise but I wish Glyde would either offer free shipping across the board or not take 12%. The money you're "saving" by not paying for shipping yourself you'll just pay back when you buy something, so you're still paying for shipping and they're taking 12% of your proceeds. This is a nice alternative to someplace like Gamestop, but I still prefer Goozex.