I agree with the above. I feel you get a better class of buyer on Amazon, you list for free, and when your listing expires, you have the opportunity to review your price to make sure your price is where you want it to be. Two cautions, they take a bigger bite out of your profits, and in most cases any item listed under $4 is almost a give away. Second, be careful of the predetermined postage, I have had some very heavy books where Amazon did not fully cover the postage, sometimes I may have to adjust my asking price to make sure I get enough.
I like Amazon, even with these flaws. I almost always list Books and CD's on Amazon over ebay.