i too am addicted to rev-matching. i just recently started doing it but i would say that about 80 percent of the time i hit the rpms right on. the other 20 percent of the time i'm either a little bit too high or too low when i let off the clutch.
it does help a bit i'm sure. but i look at it this way. which is cheaper to replace??
tranny, or brake pads?
you can slap pads on your car quickly and wayyyyyy cheaper than dropping the tranny and replacing it.