<a href="http://www.oregonchain.com/homeowner/products/chain/d_series_sawchain.htm">Here's some info from Oregon</a>
I have a couple of loops; it works OK when new, but performance goes downhill as cutters get filed back. There are filing marks on the rakers/depth guages/bumpers that are supposed to guide you when filing them but I'm too stupid to figure out what, exactly, they tell you.
I also havent figured out a way to accurately set raker height as chain is filed, beyond slowly checking with a straightedge. Oregon doesn't seem to have any easy-to-use guage. I won't buy any more of the stuff as long as anything better is available.