I own SS and suits made from the same factory as KW, and I would buy KW 100x over--especially if it's at or remotely near the same price point. His suits are full-canvassed, the construction is more robust, and the fabric selection is great. Also, if you go MTM you can choose stylistic details.
I have a feeling that SS gets discount proprietary fabrics from brand name mills so they can use them for marketing purposes (and it works).
My next jacket will probably be from KW. I just wish he did more OTR stuff in staple fabrics. I don't know anyone on this site who would choose SS over his products.
Can you expand on this? Not proof, or anything, but your thinking behind it.
Also, keep in mind there are some fabrics offered through Kent (non-CMT) in which the price range for top level SS will get you a 3 piece suit...in addition to all the things you mentioned.