The Rivet saddles look very attractive in every way in the ads I see -- I've never seen or held the real item, however.
My Brooks B17 Champion, dark brown with spiffy copper rivets, remains my standard: comfortable right out of the box, and as it enters its 4th season, I never think about it, except to admire it (frequently).
When I purchased the Raven in 2013, I bought some parts from Spa Cycles, and included a black Nidd saddle, a B17 copy. It was inexpensive, less than £30. It is now installed on my Eclipse, so is used for day rides. It matches the grey-and-black colours of the bike quite nicely. At first, I thought that maybe I'd made a mistake--the leather is thicker and stiffer than on my Brooks, and it seemed board-hard at first. Gradually, though, it's breaking in, and is quite comfortable on rides up to 75 kms (the longest I've done so far.) I expect it will be entirely OK after this season, though I doubt it will ever be as comfortable as my Brooks.
My city bike, a Norco Monterey hybrid, now has the Velo saddle which was original equipment on my Eclipse in 2003. I changed it for the Brooks in 2012, because the stiff sponge rubber in the Velo had become spongy sponge rubber after almost a decade of use, and had become uncomfortable after 6 hours or so of riding. Works fine on short rides in the city, though. I have had to patch the leatherette covering with black Sugru at the rear of the saddle (where it had cracked from repeated compression as the sponginess got worse). Magic stuff that it is, Sugru has renewed the saddle for its daily chores.
Expect I'll have to enjoy the Rivet vicariously, from other riders' reports -- barring some catastrophe, I can't see myself renewing either the Brooks or the Spa/Nidd anytime soon.