I cant sugges 796.com too (50x leverage) because they have no support.
First time I hear about this website. Is there an English version of it? You suggest them, because they have no support? That sounds wrong.
Edit: just found it 796.com/?lang=en - I think I wouldn't use it tho.
I wrote i CANT suggest them.
I switched from bitfinex to 796.com because the high fee on bitfinex works way too hefty against you. Its lowering your chances of success way too much.
796 has 50x leverage and its interesting to use such feature... though when i had questions they would not react. So i cant suggest them.
Okcoin has great support so far. The only downside i found is that a trigger order and a limit order cant stay at the same time. The limit overrides the trigger, which means your trigger is staying there but it wont get triggered. And they dont tell you. Thats really not cool. They could handle it simply the way that when the first order gets triggered that the other gets deleted, because there are not enough papers anymore.
In case you search higher leverage. I have read one can trade up to 40x on okcoin. But you need to become a vip for that.
Though okcoin has some serious trust problems at the momemt. Fine for for learning how to trade would it be still.