Also having ridden both lines, I think I would give the edge to the Feather river route, but not by much. My only Donner trip in winter was during a bad drought year, so I had no snow, but I can see why there are votes for Donner and snow.

But weather can be pretty interesting in the Feather River. I was working as volunteer crew for Pacific Limited on the April 1995 trips in the canyon that basically got rained out. The Saturday trip was stuck behind a small mudslide for a couple of hours on the way back to Oroville and the Sunday trip through the canyon was cancelled, with the train making a round trip to Fremont instead. Some really incredible amounts of water can come down those canyon walls...