For the facts, I would second what everyone is saying here. VS is -- if it can be believed -- more uncomfortable than CO in Y. In F, I'd give VS an edge.
For the opinion, I've never been really happy with the service on VS in Y. Checking in for a flight in August, my sister asked about putting her CO OP number in. "This is a CO codeshare right?" "Yes, unfortunately," was the response. I could go into detail about just how bad VS is in Y, but that story pretty much gives you an indication of how welcome CO passengers are.