From my limited experience selling on Ebay vs Craigslist, I find it really depends on what you are selling. We didn't have room for all of my china in our new place, so I sold it on Ebay and did pretty good with it. A lot better than selling it to one of the china replacement stores. Other items I've tried to sell wasn't so good. It seems like electronics sell well. Then there are items that are hot trends for the moment. You can check ebay's "What's Hot List" to find out what people are buying. Also it seems like the Ebay store fronts do really well especially for new & used items.
For all the furniture that I wanted to sell, I sold it on Craigslist. I did a lot better selling it on Craigslist than I did listing it in the newspaper. It didn't cost me anything. Plus I didn't have to deal with shipping.
What I do is go to ebay and search for the item I want to sell and I look at how many are listed and how many bids are on them. If it looks like a hot item that people are biding on, then I list it. If there are a ton of them listed with no bid, then I don't bother. I try Craigslist first.