Was out in the heavier cascade pow today. Had my choice between an O'Sin 168, Fish 160?, and my Burton 156 coil. Today the coil won, and was the perfect tool for the job. 12" of higher density powder. Lower elevations were heavier yet and getting to be those ugly bumps that start to compress and then just stop. Wider boards would have sucked.
Up to a foot I use a Coil. Over a foot, I use the O'sin. Not sure where the Fish fits in, but I'll try it when it gets a little deeper.
I like the old Coils because they are stiff enough to lay out an OK carve on Hero snow and turn on a dime in the trees. The O'sin doesn't want to perform when the trees get tracked out, and I've only used the Fish for about 1/2 a day total, so I can't really give you a heads up except that the thing doesn't like heavy tracked up snow.
Tried the shorter Fish 155 (I think), and it wouldn't hold me up all that well when the slope lessens. I weigh 150.
My son uses a Burton Asym M and loves it in the deep. Floats and carves.
Dream board someday will be a medium stiff, powder nose, 20 waist with 2cm of taper, reverse camber "Parver". No need for Titanal.