With Porter, though, you'll know exactly what you're getting.

Porter says quite clearly what the product is -- and if you choose that product you will actually get that product.

And FWIW, Porter Reserve - from my admittedly limited experience with Porter - appears to be much less expensive than WS Premium. Reserve on Porter is actually priced like a premium Y product. Meanwhile pricing for "Premium" on WS varies -- sometimes it's priced like a competitive J product, while often (laughably) priced like it's F on some NA leisure routes -- although I suppose that means that some people do actually buy at those prices.