At the risk of sounding like a retro-grouch, it is my experience that it makes no difference (to me) beyond 7/8 speeds. I have had several bikes with 9, and two (now zero) with 10-speed rear ends, and it just starts to not matter anymore.

My big complaint is the split between the double front. I like blocks (corncobs, straight gears, whatever), which results in what has historically been referred to as "Alpine" gearing (run through all the gears on the little ring, then siwtch to the big ring and do it again). It seams like the switch from the small to big ring always happens in the 60-70 gear inch range (a range that I frequently run through), which, in turn, results in a whole lotta chain running up and down the entire cog set. I have managed to avoid this on triples and MTB's, but not so much with road-bikes.

Half step works well up to about 7-speeds, but beyond that, it does not make much sense. Even at 7-speeds, you do nto get the subtle changes in ratio that you get with a block, but it is as close as I have been able to manage.