My one buddy has been working it for 5+ years. He's suited for that type of bussiness, and loves all the socializing/meetings/confrences/books/tapes/seminars/etc. His parents got involved back when the company was called Amway - they make over $1mil/year.
But like any multi-level marketing scheme, it has its drawbacks. Go a google search on Quixtar, and you'll see that a lot of people have been fucked over.