Last night I bought and played Sinners & Saints with Gerardo T. the game designer. I had a lot of fun! I really felt the tension of "simulated" combat. I could feel my character moving through the jungle attempting to take the small village of enemy fighters.
The dice rolls are different than any game I have played. I would highly recommend reading the "quick start guide" first before breaking open the main rules. The quick start guide summarizes the concepts so you can jump in as a player. Most games I play have a fixed target number. With a fixed target number gamers can usually tell if they hit before the GM says anything. This RPG mixes that up so you do need to wait until the GM rolls your difficulty before you know how well you completed a task. I like that part of the game. It keeps me engaged in every moment.
I know the game designer is open to playing introductory games with people online so feel free to contact him on Google+. He might have a game running that you can watch or participate in.