Bittrex is one of the trading platform that I trust and use for trading and for me it is fine to store your Bitcoins or altcoin there but only for short period of time, because even there are some exchanges that are trustworthy, you can not remove the fact that they are prone to hacking because they hold huge amount of cryptocurrencies. If you are planning to hold your Digibyte for long term investment, you should have a hardware wallet or wallet that you have the full control of your private key and just send it back to exchange whenever you plan to sell it.