Have only taken a course through the Mountaineers (Seattle, 2006) and was not impressed. Will be taking a Level One next year.
I do know people who have taken or teach the Gary Brill, Mountain Madness, and Pro Guiding courses. All were highly recommended. Note that the Pro Guiding course is steered more towards skiiers, so if you're limited to snowshoes one of the other two may be a better option.
