I use both Bittrex and Poloniex, JUST to purchase the crypto's, but some like ripple don't have a wallet and I don't want to have 50 wallets on my PC. I wish there was an desktop wallet to hold all the different crypto, the best I've found is coinomi, but there are still MANY crypto's it doesn't support unfortunately. Trying to trade on a platform that is constantly crashing would be terrible though, since you NEED to be on the site at all times. I'm just a buy and hold guy now, too much stress trading!