I have played Hero since before it came out as Champions (1981, for those who are counting). It has a lot to keep track of, especially for a GM ("13 stats for skeletons? The hell?"). It is very, very flexible. But I think it's a bit dated. I'm not going to look through all 11+ pages of this thread, but my main question would be: What are you looking for Hero to do? Superheroes? IMHO, Mutants and Masterminds is the game that made me abandon Hero after 23 years. Fantasy? There are plenty of easier systems that have nearly as much (if not more) 'crunch', combat-wise (Riddle of Steel, Burning Wheel). Super-cool-guy stuff in any genre? Big Eyes, Small Mouth.
But are you looking for the most generic (and I mean that in a good way), detailed system, where you have control over almost every variable? Then Hero's the way to go. Nothing even comes close.
There's also plenty of reviews of Hero 5 (aka FReD/FRED) on rpg.net.
Cheers, and hope this helps!