Dapps can be awesome when you want to avoid counter-party risk. Ether Delta is a great example; however, it's super expensive to use ED (every interaction costs $0.80-$1.60) and unless you're playing with a lot of money it's cost prohibitive to use.

Even though they had the dns hijacking a while ago, you can still access the market via direct calls to the contract. When it's time to liquidate a large alt holding back into ETH, ED is the only place I trust because I don't have to trust anyone.