I have ridden the B17, and like it. I also have a Flyer that I have never mounted... basically a a B17 with rear springs. The B17 isn't on my primary rider, until I lose more weight, but it is designed for a somewhat upright posture.

To be honest, I think those heavy duty saddles exist for the same reason that most comfort bikes have front shocks.. If someone hadn't walked for years, and suddenly started walking it would hurt for a while, just as with bicycle riding. Of course the first few times on a bike can be a little uncomfortable. In the words of Beverly Hostadter, "Buck up, sissy pants."

I am 57 years old, and a couple of years ago a friend asked me why bikes don't come with the wide soft saddles that we had back in the old days. Since I have a few older bikes, I showed her some of the saddles like we used to use... they had steel frames with a little foam and a vinyl cover... Something nobody would buy today... The answer is obviously that we don't need the saddles we had back in the day, we need the low weight and resilient bums (a term I use in honor of the British saddles being discussed) that we had back then. But, my friend is still looking for an appropriate couch to perch upon her seat post.

I think the Brooks heavy duty saddles are remakes of their saddles from back in the days, earlier than I was around, when people needed some cushion while riding on very rough surfaces... and they wanted something that provided as much isolation from the surface as possible.

Even though the Brooks line is pretty expensive to experiment with, I would personally ride several hundred miles on a B17 or Flyer before considering one of the more robust models... especially on a bike like the Linus Sport.