If all players are equal your odds of winning the jackpot are about 46650 to 1. Of course, not everyone's equal and a good player will take 1st much more often than average. I don't know much about 6 handed sng's but I would guess that it could be +EV for a good player.

That said, I can't imagine these not being magnets for colluders which definetly can screw with things.