My experience with taking rib roasts to 140-145 (which is the temp I've taken all of them to) is I get medium rare closer to rare than medium.
I have held them at that temp for 2 hours on upto 4 hours before pulling from the smokette.
As a matter of fact, the next time i do one for a family get together I'm gonna have to do 2 because 140-145 is too red for several folks in the family.
I wonder what the difference is. Is it in seering? Is it the difference between fresh and frozen then thawed? Aging?