It usually takes about 60 hours to hit a Royal Flush, so it usually takes a large bankroll to make the payouts favorable. During this time, the casino enjoys an advantage of approximately 5%. You can expect a Straight Flush about ever 6 hours, and a 4 of a Kind every hour or so. Those three hands combined make up about 5% of your total winning hands. A good basic strategy is to play on a machine you can afford to last a while, and to avoid progressive poker machines unless the payout is large (therefore offering a better return). A large payout is more than $8750 for $1.
Since the machines in this game are 10-play games, you can expect the pre-described hands in 1/10th less time.