If possible, I’d find yourself the standard carb 661 and have control over tuning your saw. Additionally, if you ever decide to use it for some milling or extrema conditions, you’ll be damn glad you can run the saw on the rich side. If you’re buying a 90 CC saw, in all likelihood, you’re not a novice who can’t tune their own carb anyway, so why mess with the M-Tronic on a large saw?
BTW, my non M-Tronic 661 has performed flawlessly here on the Northern Cali coast, where many trees are large enough to actually need a saw this size.