I mainly use Bittrex because it's the leader for pump&dump; moreover Bittrex has a very clear interface with volume, trade history, spread, change and many other useful infos.
On the other hand, Bittrex has its defects as the coin-removal ( if one coin doesn't reach a volume of 0.1 BTC ) they will remove it. Furthermore Bittrex doesn't have a referral program.
But, anyway, for me it's currently the best exchange.
I've started using Bittrex too.
But it seems they've increased the daily volume requirement from 0.1 btc to 0.2 btc recently. Any coin that fails to meet this requirement will be removed from their site.