I personally have begun to use Super Klassic (RSK) when sharp it is the closest I've come to Super Klassic square ground (RSLK) but as a dealership we sell more RM (semi chisel) than any chain we sell it prolly 7 loops to 3 chisel loops (RS). We sharpen dozens of loops of chain everyday, Stihl is far more conisistent than Oregon imho.
As a user in the wood business I've tried them all trying to save as much as possible, Oregon,Windsor and Woodland Pro, even before I was involved with the dealership I went to Stihl, it just holds its edge much longer,thicker chrome,more sharpenings, if you want a soft easy to sharpen chain get some Oregon 22lpx, it just not doesn't give you the chain life. The "new designations" are to make it easier going forward, sorry Troll gets so easily confused.
One thing you won't find on Oregon chain is the advanced system of oil delivery by concave depressions in the drive links.The tiny little dimples or indentations on both sides of the drive links will allow for a 10% increase in chain service life and will not only carry more oil, but will allow for less dirt accumulation built up in the bar increasing bar life.
The C designation is being dropped from all chain to standardize the ID system, with a few exceptions all chains will have the comfort feature standard if you question it just look on the cutter it will have a small C stamped in it,
pitch markings are changing as well it will be marked on the depth ga 1=1/4" 2=.325 3=3/8 4=.404
6=3/8 picco 7=1/4 picco