I always think of Rivendell as hardcore with lots of BS surrounding it. If you can get passed all the tweed bags and 650b wheels they have a no nonsense approach. I own an Atlantis 54.5cm and its the most versatile bike I have. Its a great tourer, a fantastic Century bike and a pretty good mountain bike if I swap the 26x1.25s I use on the road for 26x1.75 or 2.0. Rivendell makes comfortable bikes that will last, not a bike that will be out of fashion 10 years from now. Its an investment that will pay you back every time you ride.
Another way of looking at it is that they make bikes that have already gone out of style at least 20 years ago. I am not knocking that. If they appeal to you that is great. They are exactly what some folks are looking for.
I would question that they have a no nonsense approach, an awful lot of what I read there sounds like nonsense to me. What I dislike about the whole Riv thing is the pompous explanations about how everyone else is wrong and they are right; and the BS about how you don't need to wear bike clothes because they are a uniform, but buy OUR uniform; and crap like their $100 hatchet. The fact that I don't personally like their ideas on bike fit and riding position is just icing on the cake.