I've been listening to UR6s for the last couple of days in my system and think DarkAngle hit the nail right on the head with his assement. The tonal balance has definitely shifted to the less warm and slightly leaner side since the UR5 MK I/II and presents music with more energy and excitement which to be honest, is more in line with my tastes.
I've been using my Grovers between my Berendsen CDP and pre (will be assessing on my vinyl rig for now as I sent my CDP in for replacement today), and these new grovers do something really well with brass instruments too--not just air and extension but just a greater tonal accuracy then the previous versions.
In my system they are just as transparant as the Oriteks, if not more so and additionally I think they might be more enjoyable for over the long term. I don't know if I should comment here, because I haven't had time to do enough listening to really back up my gut feeling or pinpoint its origin (finals week at law school

), but something about the Oriteks signature has been just a tiny bit off for me. I'll expand if/when I can pinpoint what it is, or retract the statement all together if I find its just been a symptom of my recent stress/sleep deprivation induced irritability.
Now its time to get back to studying!