I'm quite new to this so forgive the noob question. This thread isn't meant to ask which one is better, but more what makes them different?

My first impressions are that modern razors would probably have better metallurgy, while vintage would likely possess better grinds and workmanship since more craftsmen were building razors back then.

Also, why do certain vintage brands enjoy such high demand? I noticed that Wade and Butcher commands both admiration and premium. Filarmonica seems to sell for a bit of money as well. I'm sure these are all slick shavers but is this a case of swelling demand meeting dwindling supply?

For the record, my first razor is a modern 6/8 but I have two vintage shavers in the mail (a 5/8 Williams Sheffield and a 6/8 Christensen).