The original Video Poker machines were based on Five Card Draw Poker and paid off on Two Pair or better. Because of the low overall payoff the machines evolved into Jacks or Better Video Poker which pays even on a high pair. Jacks or Better has become the popular standard from which all other variations have grown.

The most important thing when looking for a good Jacks or Better machine is the pay table. A full-pay Jacks or Better machine has the pay table at right. Notice the bonus for getting a Royal Flush when playing 5 coins.

The long-term payout for a machine with this pay table is 99.54%, when using optimal strategy. There are also some very rare machines that pay 4700 coins for a Royal Flush when five coins are played. These machines have a long-term expected payout of 99.89% with optimal play.

Almost any variation from the full-pay table lowers the long-term expected payout. As always, look for machines with the best payout table. It is not uncommon for casinos to offer the same type of machine with different payout tables.

Many machines offer pay tables with lower payouts for certain hands. In most cases the payout for a Full House and/or Flush is lower. Full-pay machines are also called 9/6 machines which refers to the payout for a Full House and Flush.

Source: WorktheOdds.com