Fot me the most important thing in exchanges is the reputation, I saw a lot of exchanges being hacked, so now I only stick with the high reputation exchanges like bittrex and binance, good customer support also an important point, low transaction fees and a lot of good coin to trade
Bittrex has included on the list of worst exchange in this year, Look at the daily trade volume of bittrex and how it goes even lower than before. So many people have problems with it and that make all of them are migrating to the binance and okex. Reputation is a good thing but the main thing is about how they can manage their customer to provide the best service.
the ol' days when bittrex is leading the way with poloniex, now they are giving bad services indeed, too much problem unresolved if i recall correctly and now their volume can't even compete with newcomers exchange, they have been foreshadowed by binance that's currently on the top
i too sure that it's kinda hard to get the customer again after there's binance and okex as a promising alternative.