This is one of the questions I'm hoping to answer in my Heroes Unlimited campaign. HU is not a terrible game, but it isn't a particularly good one either, especially if compared to the common standard of superhero gaming: Can I play a reasonable facsimile of [insert favorite superhero]? You can't play Spiderman. The combination of multiple powers plus the gadgety webshooters just won't work. Batman is barely doable. The closest you can come to Superman is an alien that's sorta strong, kinda tough, and can fly. Wolverine will have to choose between either the claws and skeleton or the mutant healing factor.
Yet in my campaign we've got PCs with superpowers who wear costumes and fight crime. That's got to count for something. But as a simulation of comic book heroics, HU falls pretty flat when played as written. Still, I'm hard pressed to take the Stick of Pain to Kevin Symbiotic, even though his game was published after the first two editions of Champions. Levels and classes, hit points and d20 combat rolls, a tacked-on percentile based skill system, these are the primordial building blocks of the second tier game systems of the eighties. Kudos to Palladium for getting so much mileage out of such a well-worn vehicle.
Normally, I fall into Ron Edwards' System Does Matter camp, yet in my current campaign I deliberately chose what may very well be the worst system in my considerable array of Superhero and generic games. Knowing that HU is based on the tired old chestnuts has been liberating for me. I've got a tremendous sense of control over the game mechanics, a feeling of been there, done that ownership that frees me to screw around with the system on the fly. I don't feel caught in a web of tangled mechanical intricacies, like I do when running D&D 3E. For some reason I feel like I might disturb the unity of verse when I have to make an underinformed on-the-spot rules-decision in some games, D&D 3E most notably. When I'm staring down the barrel of a game on the order of D&D 3E or SFB or HERO System or something like that I feel an urgent need to get it right. After all, how many editions has this game gone through and how many people have playtested and edited these rules? Yes, I know both HERO and D&D 3E are messed up in plenty of places, but they are far more coherent than a lot of games on the market. They been subject to a lot more destructive testing than many other games.
Not with hoary old HU though. Good enough is good enough. By many people's opinion the game is already a crap system, how much worse could a flubbed GM ad lib really be? There may be a correct technique for optimally shovelling pig manure, but no one is going to complain if you use a somewhat suboptimal method.