In the late 1990s I played on a blackjack team that won in the six figures on some high quality blackjack machines at Cherokee, North Carolina, until they changed the rules on the machines. We also won a lot in Vegas but the various casinos with playable machines were a bit quicker to change the pay-outs on the best machines.

The various gaming commissions are supposed to guarantee that the machines do not cheat, and my experience with machine play is that if you play long enough, you get your expected win. However, machines can be legally set to shuffle too often to allow you to get an advantage. Other machines are set at such low limits that they are no longer worth playing -- your expectation might be only pennies an hour. But if you know the rules of the game offered on that machine and the laws governing that gambling jurisdiction, you can calculate your expected win to a pretty good accuracy.

All machines are not created equal. The overwhelming majority have bad rules, and you are wasting your time to try to beat them. Rainman himself could not beat a machine offering only even money on a blackjack, for instance! But there is never any harm in checking the rules before dismissing machine play out of hand.

BTW, anyone aware of a good playable machine would be unwise to share the information because, once word gets out, the first team to arrive will lock up all the spots.