
Having done Split Mtn more times than I can count in the past 15 years, here's the Beta. If you go during high water when the Yampa is flowing (May/June) you catch it at a fun time. It is quite fun above 10,000 cfs with great waves and some big holes as well. The higher it gets, the bigger and more continuous the action is. Moonshine is awesome above 16,000 with BIG standing waves. We caught it once around 22,000 cfs and it was killer. I've seen rafts flip in Moonshine at high water and go all the way through SOB before they are caught. Pretty much just aim down the middle of everything and hang on.
At lower flows, (down to 2000) it is a bit more technical but still a great run. Too bad it isn't longer. At late summer flows when the Yampa is done (i.e. 800-1200 cfs depending upon Lodore) the run is pretty mellow, lots of rock dodging, and fairly slow. Pretty easy in a raft or kayak. There are still some playspots, especially in the new low volume kayaks.
Basically I wouldn't go all the way out there for just a Split Mtn. day run but if you combined it with other stuff it's worth it. Hope this helps.
Cheers and Happy New Year (almost)!
P.S. Hey Andy Horn - hope things are going well with you. Let's hit the Ark again at 3200 this summer, hopefully.