It's a complex issue, but it's also very simple. The BobL method is the best by a country mile. Some general caveats though;
Full chisel almost doesn't need the rakers done, almost to the end of the tooth. Full chisel is just so aggressive, and the raker is shaped very differently... generally tall and not very wide. Touching up the rakers on full chisel often leads to an unusable chain. I will generally only touch the rakers on full chisel if the chain is not biting like crazy, and then by only one or at most 2 file strokes.
Semi chisel is an entirely different beast, and rakers are critical to get the most out of it. A well sharpened semi chisel with rakers set right comes very close to full chisel in terms of speed, but will stay sharp longer, cut a much greater volume of wood between sharpenings, and lose less tooth length at each sharpening. All up, in terms of volume of wood cut per chain I would estimate semi chisel to cut 3-4 times the volume of wood. The rakers are critical though! Stihl is the best chain by far. Carlton second best but comes from the factory with rakers way too high. I will put 4-5 full hard strokes from a fresh raker file on carlton chain straight out of the box before even using it.
Raker shape is every bit as important as height. Smooth round rakers will cut smoothly, and can be taken lower and remove a lot more material. Pointy triangular rakers are by far the worst and way too agressive, they will dig in and stall at the least provocation. Flattened rakers are jittery.
A lot is wrong in that post, in fact too much to even start commenting on the details. Mostly a bunch of BS and infactual statements - but also some correct statements inbetween, like that the handling of the rakers are very important.
