Hi I like the site.
You are missing cryptsy, poloniex, and bittrex from the exchanges that I use. It would be nice to see a trade % on the chart for comparison, as well as the fee to get your coin/money out (which can vary a lot). Also cost to get money in, because some places like coinbase charge a lot to make fiat into btc.
the three exchangers that you named (cryptsy, poloniex, and bittrex ) are all altcoin exchangers and OP's link only compares the bitcoin exchangers ( trading bitcoin with fiat and vise versa )
but i am very interested to see a comparison between all of the altcoin exchangers, since i mostly do altcoin trading.