i would assume that if i had a serious problem i'd have a better chance of getting it resolved eventually with gdax.
Bittrex, like all other altcoin exchanges is incapable of properly maintaining a good status. It was all fine when they were still in the smaller form, but everything changed once they have grown bigger.
Poloniex has gone through the exact same problems. For some reason the altcoin exchanges can't deal with everything legally, which shows why they are struggling so badly with everything.
I was quite a fan of Bittrex, like how I was initially a fan of Poloniex, but they didn't manage to operate their exchange like other main Bitcoin exchanges do, which is something I find quite worrying with an eye on the future.