Originally Posted by
truckstop
Agree.
My non-expert impression: When I was handwringing at the LBS trying to chose between Rival and Force, I could feel a slight difference between the three. It's like there's more play in the lever before actuation. I didn't spend as much time messing with Red, but we also bought the Mr.'s F3 (with Red Shifters and RD) at the same time, and I rode it while my bike was apart to swap the group. Certainly not enough of a difference to me to pay twice as much, but the LBS gave us the Force group for only $100 more than the Rival group, so that seemed worth it.
The front derailleur takes twice as much effort to shift from small ring to big ring. I am using the same cable housing and front derailleur, the only difference is the shifter and the cable. I guess I could replace the cable with a gore but that is about the only change I can make.