Thanks for checking out my reviews, I hope they're helping you decide. My #1 point of advice would be to ride all the boards you're considering. Your opinion will be different from everyone else's. If you have to rely on outside opinion, check out angrysnowboarder, he writes a good review for sure. Hates Lib, though.
OK, let's break down these boards. From Mervin, we have Lib's Dark C2, TRice C2, TRS (C2?) and GNU's Altered Genetics and Billy Goat. Then Never Summer's F1, Heritage and SL. Maybe some other miscellaneous stuff, too. Here we go.
I'd rule out the F1 and Billy Goat due to their focus. They are not boards that can 'do it all.' They can do the 'scream machine' part, but not so much the playful.
The Dark and AG are pretty similar. The Dark has C2 and a little added stiffness, but still poppy and pretty fun. I don't think you want a straight up banana board for your riding. The AG is great, but maybe not for your style. You might think this eliminates the TRS, but it doesn't. Next year's TRS has C2 and since they were switching the molds this year, some TRS's this year have C2. Or so says the rep I talked to at Mt. Baker. The Travis Rice, of course, has C2. Check that out if you can. I haven't ridden it, but have heard it charges and it can obviously take on a backcountry booter.
How about the Never Summer boards? We're left with Heritage and SL. Both quality boards. I just got the chance to ride the SL in some powder, chop and steeps at Baker and can say that it held up OK. I would still go with the added stability of the Heritage if that was my everyday riding situation. As an aside, I could definitely feel the added heft of the SL while hiking. Something to think about.
As for the two sidecuts, they ride equally well on ice.
My final verdict for you would be to demo a Lib Travis Rice in 161.5, Dark C2 in 161 and an NS Heritage-R in 160 and pick your favorite. You have plenty of other choices out there (Jones, Rossignol and Smokin' Snowboards all have Magne models, Smokin' even with 3-year warranties) but that's the best advice I can give you based on what I've ridden and similar boards in those lines.