Vipec is awesome but don't buy a management system because it has "autotune". Such features are 99% gimmick.
Vpro is fine but you need to be a dealer to tune it, so if you plan on tuning yourself skip it. Otherwise it's good.
Tuning the fuel map is the easiest and fastest part of tuning a car, especially on a load holding dyno like a mustang or dynapack.
Aside from the actual tuning, any decent system will run closed loop based on feedback from the 02 while you drive, to make basic corrections under normal driving. A $150 megasquirt 1 will do that.
If you plan to tune the car yourself, download the various tuning softwares and see what feels more intuitive. Pretty much any system can be tuned to make a car run well but you need to know the software.
If you are planning on using a tuner, use what the tuner is comfortable with.
Ensure the system has enough inputs outputs to do what you need it to do.
As a small update on my end, i just replaced my megasquirt with a VEMS and it is fantastic.
