My worst rig was a first year 1994 Subaru Outback. After the second spin during that first Winter, I had enough. It also was pretty horrible in anything other than small amounts of fresh snow and the tires floated horribly otherwise. Maybe it's just that my expectations were higher for snowy weather for AWD. The AWD was essentially useless going down mtns. It was a good dry weather car.
I've only owned one TC, and it is my Host. It's been good enough. I still haven't found one I'd rather have. I liked it with my F350 SRW, but of course, the F450 handles it better.
As far as worst performing RV combination is concerned, that would be pulling a 24 ft high wall fiberglass trailer with an Ford Expedition. In theory, it was well under it's capacity, but with wind, it scared my wife to death.