ZERO. I got a 1948-50 Gillette Superspeed from a family friend in pristine condition. Put a Feather blade in it and WOW.
He and his wife were moving into an assisted living facility, and I spied a batch of vintage razors. He hardly used them because he used an electric shaver. I told his son that if they were going to throw them out or give them away, I would gladly take them.
He has since passed away, and I think of him fondly when I use it.
To someone like me that keeps buying vintage razors, best shaving changes as (a) I keep getting more and (b) I rediscover razors I already have.
If you ask me today, my best shaver is a Schick Type E2 Injector with the head that opens that I paid less than $10 for on eBay.
Since this is a DE sub-forum, my best shaving DE is a Canadian Goodwill Special #175 on a fat Tech handle that I think I paid $15 for. I have every NEW and Goodwill, both types of Old Types, and a couple of rhodium English Aristocrats and I prefer this Goodwill to all of them.
My smoothest shave is from my Yingjili I paid $1.80 for. My best shaver apart from that is either my S&S Precision ($13), or my post war Gold Tech ($1 at a flea market).
5$ for my NOS Rotbart Mond Extra #15 which gives me as good shaves as the best of the many others I own between 0 and 200$. It is my only razor that gives me perfect shaves with any blades you will use. I barely use this razor at home because it is not the nicest, but I have it often with me on vacation traveling. I hope someday someone will make a perfect stainless steel copy of it and then I will be the first buying it.