I'm about to pull the trigger on a new Stihl backpack blower. The BR 450 and BR 600 have very similar specs and the price is within $20. The main difference is the BR 450 is a 2 stroke. I know you still have to mix oil in the Stihl 4 stroke models, but I don't care about that. My concern is life expectancy, maintenance, and ease of starting. Opinions please!