We need stop orders. Most of traders can't afford to buy/develop a trading bot and can't sit in front of monitor 24/7.
This. I care far more about this than limit vs market orders. They're tools, and both are useful and necessary.
The lack of stop orders on any exchange is a travesty.
Did you already take a look at
Kraken?. It's in private beta right now, but you can request an account if you're interested.
They have plenty of options for closing the trade, including stop-loss, take-profit, stop-limit and about 7 others. Looks quite promising if you're the pro-trader type.
(I'm not affiliated with Kraken, just participating in the beta.)