I remember vinyl seats on the Toronto subways........while plastic-y and dated in appearance by today's standards, they were comfy (padded). I don't have any inherent issue w/them, done properly, as with leather, faux leather, and fabric there is wide variation in quality, appearance and durability. Suffice to say, you generally get what you pay for and better material costs more, and like anything, it must be maintained.
Personally, I see nothing wrong w/fabric, padded, seats. Today one can get these with rip-resistant/rip-stop characteristic minimizing slashing or accidental tears, and with a high degree of stain resistance. They just cost more, and of course, needed to be wiped down, and periodically re-done.
I think we really should see a report outlining the different upfront and lifecycle costs. I know I'd prefer to spend more in subsidy and to a lesser degree fare, for a better product.
But let the public have at the numbers. Is .05c savings per fare or $5 per seat up front worth the decrease in comfort and style? In fairness........what if its .50c per ride?