It depends only on your experience and knowledge. If you do not want to take too much risk - then your choice is stocks. Bitcoin is a very volatile currency also.
But i prefer trade with BTC because there's a bigger reward. Btw, i trade on Monfex. It's a very convenient and safe platform - check it out.
If prefer trading in stocks which really gives profit then it is good for you. Indeed we know bitcoin is very volatile with a high risks when investing. In bitcoin many opportunities on the users so better understand and learn which option is really good for a trader.
Of course BTC is volatile and there're some risks. But i think that trading is impossible without taking these risks. Personally i prefer to hold long positions with BTC. What about you?