From my limited experience.... Ninja Trader is the best and most flexible "try before you buy" platform. There are also lots of potential third party consultants or programmers available. All the others have limited trials or reduced features.
Here's something else I just ran into on Facebook from NinjaTrader. It's a site that teaches you how to program with NinjaScript. Looks pretty good but I don't have time to look into it more. Let us know if it's helpful. http://www.ninjaprogrammingschool.com/