For me reds are great for typing, because just pushing the switch a little bit, your keystroke is almost guaranteed to register. Plus with the audible-click of the Kinesis turned on, it almost feels tactile! Love my Kinesis LF with the red switches, highly HIGHLY recommended.
Input Nirvana who is the only other person I know that tried red switches on a Kinesis (and unlike me didn't have a problem with the browns being frictiony) also reported he likes the reds on it.
On the Kinesis contoured, because the keys are positioned in various angles in the "bowls", gravity doesn't always help you, you don't push the keys straight down as with other keyboards. Some you push down, some you push slightly forward, some you push (or pull) slightly backward, notably the arrow and [] keys. These varied motions are easier to carry out with the lighter red cherry switches.
Of course, personal preferences may overcome the above arguments, so YMMV, but I honestly think the red switches on the Kinesis Advantage is a perfect match, except maybe for people that are heavy handed and can't adjust to typing lightly.
Anyway, owning 6 Kinesises (2 of them with reds, 4 with browns) I use both regularly, and reds are by far my favorites.