The only bad thing about using some of these other smaller auction sites is that you're auctions aren't gonna get the exposure that Ebay can give, thus, your items will more than likely sell for a lot less
The biggest thing I hate about Ebay is the way they raise their fees. They'll knock off like 5 cents from a listing fee and boast about it, then when you scroll down, you'll see that they raised up to final value fees enough that the 5 cent savings in listing isn't gonna do much when they pull more out of you when the auciton ends.