This is a re-posting of a 2008 experiment I ran on my Facebook page
One aspect of the supers RPG market that I've been commenting on for a while is that there is a dearth of "focused" games, unlike the fantasy market. Fantasy gamers know that D&D is going to offer a very different experience than Runequest, which is in turn different from Warhammer, and that one shouldn't use D&D to capture the feel and tone of Warhammer, and vice versa. No comments on which is a mechanically superior system, as they are aiming for very different things.
In contrast, until recently the Supers market has been dominated by systems that claim to do all sorts of Supers equally well - they can handle Heroes for Hire and the Avengers, Dark Knight style Batman and the Justice League, Tom Strong and the Authority all with equal ease. In my experience, this is hogwash, and while I have played enough supers systems that I could say that I know for sure, I want to do a little experiment: taking a single character from a finished campaign and seeing how he looks in every major system I can. How do the mechanics of the system shape the character, what he can do and how he might be played. I am hopeful that some of the other supers gurus reading this - whswhs wrote GURPS Supers, Chadu wrote Truth and Justice, mnemex was a playtester for Marvel Diceless, Cambias wrote for Hero, and whoever else has a preferred system - might take their hand at translating the character to their preferred system, but if not I'll go it alone.
The character is Dr. Zachary Zevon, the Indestructible Man, the Smartest Man on Mars, from Dan Harvey's defunct Liberty League PBEM. Dr. Z is the leader and Reed Richards analogue of a team of adventurers and explorers who gained their powers over kinetic energy via a failed attempt to recreate the Philadelphia Experiment (the offshoot technology of which was what made Martian colonization after WWII possible - the game took place in New Philadelphia on Mars). His particular power is projecting invisible force fields, which he uses to give the world the false impression that he is personally invulnerable and superhumanly strong. His force fields are highly versatile, and he also has an array of personal inventions that he carries with him on missions.