A lot of people compare the Sam to a Surly LHT or other similar touring style bike, but I don't think that's actually all that accurate. Even when you compare the geometry of the Sam to others, it doesn't quite match.
When I picked up my Sam, the dealer (one of the few that actually carried Rivendell - not sure if he still does) indicated that the Sam would probably be good for "short tours" but not extended ones. Even one of my friends who's into racing thought he could go pretty fast on the Sam when he tried it out. The Sam is described by Rivendell as a "country bike" - go anywhere, do anything - within some reasonable limits. The closest I can describe it is some sort of a like a roadish style hybrid, with some gravel grinding and touring thrown in - I guess country bike is pretty accurate.
As for build kit quality... honestly, I don't have much to compare it to: all I can say is that it rides nice and smooth.