eSignal is absolute king. Has kicked the crap out of TradeStation long ago. I cancelled my TS months ago now.
Is also the most reliable datafeed in the world and has been so for over 10 years now.
Also has the most useful charting package, the charts are scalable etc, you can get anything in .efs, it's awesome, and the trading system language is awesome, too - if you like coding. And of course the service is excellent, which does count.
Regards,
Scientist.