Can you please expound on how/why you came to that decision? I'm rulling out the 8520 and 600 simply because I want a simple 2-stroke. I don't mind a strato though. That leaves me with the 802, 8050, and 770.
I think for the same reasons you are considering one as well.
For one less moving parts.....the 600 does have a scheduled maintenance from what I read......valves to adjust, head to decarbon, etc. Plus the problems the 600 had when it was introduced.
Second, it appeared as though both had near the same power and near the same weight......I don't know that I could detect the weight difference. Shindaiwa has always gotten a reputation for being bulletproof, but at the expense of added weight. But this one is competitive with weight even with a higher displacement.
Third, I kept reading about how the stihl would run out of gas with fuel left in the tank. Whether this is true or not I don't know.....just read about it a few times.
Plus, 4 strokes is 2 too many!
Just my thoughts/opinion.
Let us know what you end up with...............
Waylan