Oh that's easy...
Yeah. See, I'm not looking for 'challenging systems'. No, no. Thank you for coming complex mechanics. Your resume' is very impressive, but we're going another way. We'll keep in touch (tosses resume' in the garbage).
Champions is the exception to the rule, and honestly I couldn't exactly tell you why. That is, why do I like it so much if I despise complex rules so much? I don't really know. At least I can't put my finger on it. Champions just works. It allows for the imagination to do what it wants to do, but it gives definition to it so that your imagination, and my imagination can interact with each other using the same rules.
In theory, that is the goal, and purpose of all RPGs, but all RPGs don't do that as well as Champions does
Also, although generic and adjustable, I firmly believe that Champions Superhero gaming has a very distinct feel. It is both over-the-top, Silver Age-y and rather brutal, with the addition of Hits, as well as Stun showing that a Super versus a normal person is a scary thing.
In the end, I am really glad I learned this game, and very happy to have been taught it by my friend William C. He showed me how this rather crunchy system is the cobblestone streets beneath our feet. Solid, beautiful, with occasional awkward bumps, but essentially just a well made road for getting me, and my Supers games to the place I want them to go.
Thanks Will. Thanks Champions.