Sidewinders are pretty cool, just give them a little space and they won't bother you. Diamondbacks can be cranky at times, and the Mohave Green is just plain nasty. The Greens are just arriving to my part of the world, and I keep Sam strictly away from their area.
Sam and I have had several really good training sessions with sidewinders-he avoids them really well (at least so far. I have nightmares with a snake hanging off his nose).