I really do not know much about the last two you mentioned, but for bitfinex and binance, these are good exchanges that have been able to do well over time. I strongly recommend binance as well based on liquidity, trading fees, and then the support which is pretty good for me.

The UI too is okay but since I am always using APIs to trade on tabtrader, I usually do not pay so much attention on the exchange UI. For bittrex, based on loyalty, and reputation, this is one exchange I will never stop using, and even though sometimes, the fees in binance has spoiled me, I still feel confident with the bittrex exchange.