I can only speak with regards to KM2's and Toyo MT's 35x12.50.
Deep snow, I would say they are about the same for offroad performance. I would even give the nod to the BFG's as they are a little narrrower and cut thru better.
On-road performance with light snow and slippery conditions, Toyos hands down. They come with light siping in the center of the lug where BFG's do not. I have been scared by how slick the BFG's were on questionable conditions, where I have always felt sure footed on the Toyo's. Again due to the width the Toyo's do like to float a little more in heavy slush, but with the siping it is always predictable. I do a lot of driving (600+miles a week) and I run the Toyo's year round, and won't ever go to do a different MT again.
**Edit** For the Ontario fella's here that know the area I drive from Woodstock to Stratford everyday, and go to my farm near Owen Sound every weekned, so I travel and live in a bad snow flurry region. I've seen my share of pretty bad roads, and venture down as many no winter maintenance roads as I can!
2007 Dodge Power Wagon - Inferno Red Quad Cab, G56, KRC 210X cam, SRT8 JGC seats, 35x12.50 Toyo MT's, Offroad lights behind the grill, Warn wireless winch remote, Carli front Diff Guard, Carli Long Travel Air Bags, On board air complete w/ train horns, homemade hidden gooseneck hitch, Homemade locker bypass, upgraded Mopar steering box, Centerforce clutch
1998 Dodge 2500 Laramie, QCSB 4x4. 24V cummins, completely rebuilt chassis with '01 1500 body installed, full gauges, Edge drag comp box, performance 47re built by me, 35" Dynapro MTs on 3rd gen wheels.
2002 Dodge Ram 1500 ST 4x4 Quad Cab 4.7L Bright Silver, HO Cams, 12,000 lbs Winch mounted behind bumper, 4.56's, 2500 factory tow hooks, 35x12.50 Toyo MT's, Air-Lift Ride Control bags, homemade hidden ball gooseneck hitch.
1987 W100 - mild 360/727 combo, running my 35" Toyo MT's from the '02. Ramcharger D44 w/ warn hubs, Warlock seats, 2nd gen center console
1987 Dakota - RCSB, 413 big block, LT headers.
And a few jeeps for good measure.