Sorry that no owners have responded to this. I drove an IS-F for a week for review purposes, and earlier owned a GS 400 for a while (father's ex-car). The IS-F seemed very livable in day-to-day driving aside from being very thirsty. I did not have it when there was snow on the roads, though. I suspect that with proper winter tires it would be drivable in snow, but you'd have to exercise more caution than in something like a Camry.
I did test an IS 350 AWD with snow on the roads. Absolutely no trouble driving it.