Man, I miss those boots… Wore them into the ground.
I have owned three generations of the Shimano MW winter boots and they are good. Definitely better then any sock/cover I have tried for commuting or nasty winter MtB-ing.
Did not like the Defroster (Specialized); both awkward fit (normally I find their shoes a very good/neutral fit for most people) and awkward to walk in.
I am one season in on a pair of North Waves and I would recommend them above anything else (assuming good fit) with the Shimanos a distant second.
The North Waves dual Boa system makes it possible to get the shoes tight enough for out of the saddle efforts (Shimano all Velcro is sloppy) they expand//contract better to fit well with different sock thicknesses so you can further adapt for cold//less cold rain, and the soles are WAY stiffer for pedaling while still being fine to hike in.
Keeping in mind I'm more sensitive to soft/flexy shoes then most people I know.
My first pair defrosters fit well and worked pretty well, but my puppy chewed them a bit. I had the Velcro straps reattached but punctured neoprene collars got the lumpy shoe goo fix which wasn't ideal. So I got a new pair but the fit is bad. I had to get one size larger than normal and even then it's not quite right. I can't wear the Shimano's because they don't come down to my size, 39. I wore a 40 for a season so I know the grip and warmth is good but that was a touch too large.
Debate? Bikes are made for riding not pushing.