Ctcw
I've sold and bought a couple of smaller items. I like the fee structure, but it's got a problem with number of users. It's getting enough traffic to get by (as far as I know), but it's nowhere near the traffic that ebay gets. That means your items get fewer looks, and fewer bids. Especially important in this vein is the fact that it's a specialty site - no one gets to your auction accidentally while searching for something unrelated to the hobby.
I recommend putting stuff up at appropriate prices - don't do the '99 cent listing and they'll bid it up' thing, or you could get stuck selling it for 99 cents.
I find the fees to be reasonable (though I paid for a lifetime sub, so I don't pay anything anymore). I haven't had any trouble on any of my transactions.
It very much has the feel of early E-Bay, before they got insane with the fees and the forced PayPal integration.
I REALLY want them to implement e-mail searches. I hadn't realized it until someone else said it, but I really want it now (I note that I've got about a dozen e-mail searches running on ebay). Or, at the very least, a way to bookmark or save searches to come back to later. That would greatly improve my ability to keep an eye on things there.
Overall, I like CTCW, and I hope it keeps going. I keep looking, but I don't have much to sell right now, and I haven't seen anything I needed to buy recently.