IMO, magnetraction holds a bit better then the variogrip on NS boards, however after riding a bunch and dulling the edges, the Libs maintain their edge hold better. I really liked my Proto on the ice when I bought it (no detune of the edges) but after I ripped around for a few weeks the edges dulled out it really lacked ice hold compared to my T. Rice. That being said, as long as it wasn't a bulletproof day, I would ride the Proto. I took that thing off some good sized jumps (35+) and it was fine. I also prefer the base on the Proto as it seemed to hold wax better and feel less sticky in-between waxings. And the carbonium topsheet on the Proto is really tough. My Libs always get torn up really quick.
That being said, you will likely find a TRS on sale before a Proto.