I’ve used the winterra for the past 2 winters. I don’t know if it has a nylon shank or not, but the sole is much more supportive than most pac boots. They work well with both snowwhoes and crampsons. On the downside they are not lightweight and they are a little narrow for my slightly wide feet (I wear the wide version of the montrail hardrock for 3 season hiking). I should have sized up.
I believe they have been replaced by a new model. The Thermo 8 and/or 6. Campmor still hase a few sizes for a very reasonable price.
Hope this helps.