JoB is short for Jacks or Better, which is a video poker variant.
Unlike slot machines, video poker machines must act exactly as if the cards were randomly shuffled and dealt from a real deck of cards (this is Nevada law). So, in order to change the odds of a game, the casino can't make it less likely that you will get a good hand -- they can only change the payouts for those hands.
With Jacks or Better, most paytables are the same, except for the payouts for a full house and a flush. "9/6" refers to a game where the full house pays 9x your bet and the flush pays 6x your bet. 9/6 JoB is a pretty good game -- it returns 99.54% of your coin-in with optimal play (and it is a very easy game to play optimally). This is the best widely available paytable for JoB.
8/5 is much worse. Because you make a flush and a full house each a little over 1% of the time (ballpark) the pay back of 8/5 is a little worse than 97.5%. In other words, you will lose about 5x as much in the long term on an 8/5 game as on a 9/6 game, with optimal play.
Last edited by VegasGambler; Jan 9, 2015 at 11:34 pm