Theoretically, you can winter camp in just about anything, it really just depends on how extreme the weather you're expecting to be. If you're camped up on a mountain ridge with gale force winds and the potential for big snow loads, you need a tent that has lots of poles and a low, round design to keep it from getting crushed. So for that, you really want the Mountain 25 (I have one from 20 years ago).
The NF Mountain 25 is kinda trash. Very heavy for what you are getting, quite small inside. I bought one and the pole bent the first time I set it up.
If you actually are serious about spending the money necessary to get this type of tent you should consider:
1. Hilleburg tent
2. Big Agnes Battle Mountain 2 or 3 (similar structure to NF but lighter and just as strong from a better and more reputable tent brand).
3. Samaya (extremely light, extremely expensive alpinist level tents)
I used to (10+ years ago) haul an NF Mountain 25. Extremely heavy, yet comfy, and bomb-proof. I did not really go out much in storms, especially since where I was located (central High Andes) everything is above treeline.
I'm currently using a Sierra Design Cascade (if i got the name right). It's not as comfy or bombproof as the NF, but is way lighter and more compatible for a do it all tent . I also have tarps for lighter missions.
It really boils down to what you want it for. The NF was great for base camping. The Sierra is more friendly for traverses, and pretty cheap too. Both are 2 wall, so condensation is not an issue.
I would think that being based in the cascades, you would want something where you don't get wet. I think I've slept in the MSR, its light, but extremely tight and delicate.
AngeloPappas
