We do speak a lot about alternative sites to eBay here on the forum quite a lot. Amazon does have quite a strong traffic flow, so is marketplace everyone should be paying attention to.
My advice always is that you should cover as much of the market as you possibly can, taking into consideration your time and your budget. Of course the larger, more established sites will usually cost you upfront, where as the smaller, newer sites will usually be free to list so they can attract business.
Pro's and cons whichever way you go, but the better you are covering the total online marketplace, the better your chances of making sales!