The R1 is an XC race brake- the fact that it can do dh trails at all's impressive but it's just the wrong tool for the job.
Indeedy. Hence my suggestion they are OK for harder stuff if you are a lightweight like me!
In fact, i'm impressed with my R1's, and after a recent massive OTB on the La Varda trail (luckily not over the edge.....) i rode the second half of that trail, and another couple of techy steep trails with my brake lever hanging on by a tiny bit of bent ally (the main lever had snapped from the impact around the reach adjuster thumbscrew!)
But, what i don't like is twofold:
1) Aiming to get the weight down (as you would expect for an XC brake set) has left the system with loads of really small parts, that make "field repairs" really difficult, and the pads don't last long when abused because they are so thin / small area
2) The costs of replacement parts, and the fact you can't get individual components, so end up buying half the system just to get one screw!
So, whilst i'd heartly recommend anyone to run them for more XC duty, if they want a very light and powerful system, for proper "AM" or "Enduro" use, they wouldn't be my first recommendation.