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Same here. I am using ignitionX (mojo1), because when trying compiled windows apps on several badly maintained PCs (XP and Vista) mojo1 was the tool of choice that ran out of the box on nearly every device. And I even tried several other game making tools like GameMaker, Unity, Defold, GDevelop at that time.
antomCX is maintained and in development till now while Pyro is NOT, but I also think (correct me if I am wrong) Pyro has more features!
feature wise I can not see big differences, but that is just an impression. To me the main difference is that IgnitionX and Pyro is more modular compared to fantomX, i.e in the former you usualy extend classes like iLayerSprite that have build in methods for timer, collision etc. to build your game objects with the functionality you need.
In fantomX everything is controlled from within the engine class, where you have callback methods that are triggered by events like collisions, transitions etc. and in those callback methods you have access to the objects that triggered the events, so you can react accordingly.
But for fantomX/fantomCX
@MikeHart is the person to ask.
If I was starting now, I would rather chose a framework, that is used widely and/or maintained at the moment.
BTW pyro seems much easier to maintain than ignitionX because later is a beast regarding the dependencies of the different modules in it.