Surprisingly, the Dunlops turned out to be pretty good on packed snow and ice, so I was able to make it through the winter but I was never confident in the 4runner's capabilities when the road conditions were less than optimal.
I recently bought the Revos and even though it's now summer, the 4runner simply handles a lot better. With the Dunlops, it felt like the truck wandered, requiring constant steering corrections. Now, the vehicle tracks much better. I get a feeling that this next winter, the 4runner will be much more capable.
As a last note, a lot of people mention that the Revos are a bit noisier, but I didn't notice any difference. If there is a difference, it's certainly not very noticeable.