1.) Multicharts for intra-day automated systems
2.) Amibroker for EOD mechanical systems
3.) Ninja Trader for discretionary systems
-Multicharts is very easy on your systems resources and it runs flawlessly making use of all your systems cores. Quite fast for back-testing and optimizing.
-Amibroker is a bit clunky for intra-day trading but extremely fast for back testing EOD strats.
-NinjaTrader is a clunky price of 'software' that is resource intensive but handles the RT data flow the best of all of them in that you can program heaps of ways to handle that data flow.
-Amibroker probably required the biggest learning curve, MC has probably the easiest language. NT has the most third party add ons and is easily the most commercialized now.
I have all three and actually use two for live trading and NT for SIM at the moment.
-Amibroker trades 20% flipper
-MC trades my system and another third party system
-NT i use for SIM trading using the DOM.