SS mtb is the bomb. I got into it when I saw my first Bianchi Boss in a magazine and ordered one the next day. It is not for every course, but if you ride the bike to be riding a bike then SS is the way to go.
Sometimes mtb riding with gearies is difficult as your rhythm is different than theirs. You charge when they shift ect. , but after a while they know how you ride. I have loaned a SS bike to friends plenty and I have never heard one “this sucks” vote at all. In fact most buy one soon after their first ride.
It is bullshit to buy into the “knees” story as I am over 50 with knees too crumby to run 30mi a week on, and have no problems SS mtb riding. I do not advise doing Xterra Maui on the SS. That really sucked. Aloha G