BTC-E is the best. Here are the reasons:

5. Right now, the largest BTC volumes.
6. Never been hacked or DDoSed.

Their FAQ page (https://btc-e.com/page/2) states a trading fee of 0.2% regardless of your trading volume, so it is not that bad.
For comparison, Kraken (https://www.kraken.com/help/fees-and-pair-info#XXBTZUSD) charges a 0.35% if your volume is low.