I use them rarely when someone sends me an altcoin collateral.
The exchange rate is better there because most big traders don't want to risk by depositing their funds but its a good opportunity to make some profit if you have the knowledge and time.
Yeah for this reason I traded there because the exchange rate was better than on other exchanges and the 1% bonus encouraged me lol.
atomicat, have you tried to use them recently? At least for me, the site looks looks like working fine (deposit, trading, API etc) - except of no withdrawal, no answer to tickets regarding the withdrawal issue (also their QQ number does not seem to exist anymore), as I have just written in another thread today. Kind of reminding the last weeks of Cryptsy (and some other exchanges)...
I would answer here that I haven't used them for many months and don't know how things are going recently but I see a huge trading volume.