I've never played on one of these machines, but I dabbled with systems on
betfair roulette & managed to turn £100 into over £2k in the course of 2 weeks, but then went & lost the lot. In the
betfair forum, other disgruntled 'losers' were speculating that the computer programme learns your betting habits, so the only way to win is to keep switching strategies. I'm going to leave it alone for a while, then use the same system, but this time quit while I'm ahead. This will require having a target & the discipline to pack it in at that point!