I have a Logosol F2 with a 4m set beam (extended either side again) running with a Stihl 441C which is around the 70cc mark. I'm about to the push the button on a bandsaw mill purely for the reason noted by Trainee neophyte, the volume of waste wood is phenomenal. I use a low profile bar & relevant chain and whilst usually not an issue sometimes I get some really really nice wood and it's heartbreaking to see a large percentage of the tree turned into hamster bedding.
I'm quite fortunate in that I own a small part of the forest I live in, getting the trees is not the issue, it's moving the things around during the entire processing phase. I'm currently looking at the cost implications of building a log arch over buying one off the shelf. I have a UTVs so this makes sense but you end up with the issue of getting logs into position, both into the arch and onto the mill.
The cost of lumber these days is getting a bit silly, if you can harvest your own it makes a lot of sense. That said, it's a lot of work, rewarding but a lot of work.