Being on my 5th Baywindow Westy right now, I have to agree on some comments and disagree on others. The seats when new were extremely comfortable, but after many years, of course they are less so. As the sisal padding breaks down, you lose the comfort; most sisal on baywindows is found UNDER the seat in a messy pile these days. :-) So I disagree on that issue. Rebuilding the seats restores the comfort.
I DO agree on Baywindow wandering though,; driving the I-5 even after my Load Range D cast iron sidewall tires and new steering box leaves me in a cold sweat. I don't know why they handle so poorly compared to a vanagon. Vanagons have no such side wind vices as far as I can tell.
As to interior comfort; well of course the vanagon wins hands down IF you need an interior stove and real fridge. That technology was just not common when Bays were built. I've got a deluxe now with an inside stove and a fridge but they are very primitive.
When it comes to beds, the two are even in my opinion.
Regards,
Courtney