The system is pretty easy to master. With someone who's read the book as a guide, a group can easily learn it in a single session. Familiarity with poker hands does help, but the book also includes a handy reference for that. Dust Devils is built to be ideal for 1-3 sessions of play (as opposed to "campaign" style play).
One other note -- sometimes new players are frustrated with deadly hands that diminish a characters Scores quickly. There are two important things to remember about this. First, keep in mind that it's ok to Fold. That rule too often gets ignored. It helps build tension and helps avoid those deadly Full House hands early in a game. Second, consider providing players ample chips so they can help deflect some of those painful hands as needed.