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Next, a little history. Hero system began as Champions, a superhero rpg. It was revolutionary in many ways, and did a great job creating the comic book genre. The rules, however, were in need of serious balancing. Other supplements came out, including for the wild west and espionage.
Champions II followed and was an improvement, but the system (IMO) didn't really come into its own until 3rd Edition. This edition cleaned up and consolidated a lot of the rules. Instead of separate rulebooks for different genres, everything was included in the main book. The worst complaint I can make is that the binding was lousy, so the book fell apart fairly quickly.
Fourth Edition (IIRC, called Fuzion) appears to have been a bit of a waste. I glanced at the rules, but never used the system. As another poster said, they weren't terribly well written. Ironic, since the idea was to make the system simpler...
Fifth Edition is the latest. The rulebook is fairly well organized and, best of all, has tons of examples of powers, rules, and campaign ideas. The system also has a lot of support - if you're going to use the system for superhero gaming, definitely pick up Champions, and consider Millennium City (a city book) and Conquerors, Killers, and Crooks (a villain book). There's also quite a bit of free material on Hero Games website. If you want a character creation program, Hero Designer 2 is available - I'm still not completely sold on this product, but for now I'm forcing my group (including me, the GM) to use it, to give it a fair test.
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