I'm just a "baby" when it comes to the 1/4 mile stuff...seriously, probably at most 10-15 passes TOTAL...so the shift-light is a life-saver...seriously, when you do track as rarey as I do it just gets too busy when you're finally there, a shift-light lets me focus on feeling the car move off the starting line, engine revving and when the light goes off I bump the ratches shifter into the next gear.

Now from a street point of view I use the tach all the time..somehow it seems to be 2nd nature there...probably b/c we all spend so much time on the road as is, maybe it helps that my daily driver is a 5-spd car anyways and I always catch the tach there.