I spent a lot of time in one and liked them.  They were just right for one person and comfortable to run all day as far as I'm concerned.  The 8000s blew them out of the water of course and the new Rs are better yet.  I'm one that tends to feel more comfortable without so much space around me so they were cozy for me.  Once they came out with the thousand series cabs they really should have been shot for not getting that done sooner.  They had the engine and the transmissions down pat, the cab was really all they lacked.