I have a Granberg I run on a stihl 660. That's how i get pretty much all my lumber. It is a rare occasion that I buy a board. I only cut trees claimed by weather or I salvage some logs from friends and family that are firewood cutters. It is indeed a lot of work but its so rewarding in the end..
What I like about it most is you you can mill where you find one laying down, thats kinda a plus over bsm's. I been using a Jred 2186 to mill with, Thats kinda pushing it but runnin it fat and making sure I have cool down times in my cuts, so far it's been a beast, but nothing like a 660.
You ever use a Carter AccuRight Log Mill? I been using this for a couple of years, for limbs and stubby stuff. My band saw has a pretty decent re-saw for it and only issue I have with using this is I have to have some roller stands to help with support so I dont have too much weight on my saw table...