I thought the Oregon version is built with plastic components, and the Granberg is all metal.
I have one at work that has the plastic on it, and i thought it was Oregon. I have to to look again. Anyhow, the plastic has too much flex in it to support the file angles well.
the metal flexes too... IME, they flex about the same. if you're flexing the plastic sufficiently to really affect your angle, you're pressing too hard...
The body's some type of plastic but the nuts are real metal inserts into a groove so when you tear them out from torquing down the wing screws you can just replace them instead of trying to fix the whole metal body on the granberg...