I have had no problem in the snow. My van was SRW originally and I converted it, so it truly is apples to apples. Keep in mind that being a van, most of the weight is over the rears, so that helps a lot. In some conditions, the extra tires help. Especially in really deep snow where extra tread width keeps it from sinking so far. Only time I don't like it is on frozen slush, where the rear tires constantly "fight" over who gets to be in the rut. I have thrown on the chains a few time, but only because I was towing and ODOT had checkpoints or it was during their heavy patrol times (i.e. saturday mornings). I just use regular quick-fit HD chains, which work just fine on a dually.
I'm in the snow almost every weekend all winter long, and usually tow through snow a few thousand miles/year.
2000 Ford E450 V10 VAN! 450,000+ miles
2014 ORV really big trailer
2015 Ford Focus ST