I'm not sure whether Bittrix or Poloniex is better is just depends on your trading goals. If you are looking for a place where you can find almost 300 different altcoins then Bitterx is defintiely better than Poloniex. And moreover, you have to look at the volume of the exchange. If you are trading big volumes, then you have to use an exchange with big volumes. Actually right now one of the best ways you can make the funds is altcoin trading sometimes even investing. In order to invest you have to look at the underlying technology of the project, recently I made one investment in the project which is called Cryptics. These guys have created a trading platform which is backed with AI and it predicts the price with high 70% accuracy rate. I advice you to check it out, it's really helpful in trading as well.