if you can put up with the added volume of water (and diluted pre-boil wort) you really bump up the efficiency with more batch sparges. I usually do 2 but have done 3 batch sparges to find out how high of efficiency I can get. (with three it is usually just drain the mash tun, 1st batch sparge addition, stir like heck for a few minutes, wait a few minutes, vorlauf, drain tun, 2nd batch sparge addition, stir like heck, volauf, drain). and occasionally rinse grains once again. Doing a barleywine I was still getting runnings of almost 1.040 after collecting my pre-boil volume! I can see why people do partigyle! Lots of sugars left in the grains.
That being said, I don't really obsess about efficiency...grain is cheap. I don't mind that my efficiency is in the upper 60%'s...just know what it is and move on.