The problem with most reputation-based systems is that they don't operate the same as in real life.
Anybody's "opinion" is valued (reddit voters, upvoting in SE), and you're not risking your reputation when recommending incompetent individuals (look at the lousy suggested edits approvals at SO).
They either should be economically balanced (you GIVE 1 unit of reputation to someone, you lose it) or they should resemble reputation in real life.