What do you use the truck for?
Different performance bias between the two tires...from tire rack's description:
The Michelin LTX A/S is a durable, premium, highway all-season light truck tire designed to meet new vehicle Original Equipment requirements. The LTX A/S was developed to provide particularly smooth, even wear, low noise and good fuel efficiency, even in demanding commercial applications.
The LTX M/S2 is Michelin’s Highway All-Season light truck tire developed to combine long tread life with all-season capabilities for vans, pickups and sport utility vehicles, as well as for commercial vans, shuttles and chassis cab vehicles using light truck tire sizes. The LTX M/S2 is designed to combine a smooth, quiet ride with year-round traction in dry, wet and wintry conditions, including in light snow. Compared to the original LTX M/S, the LTX M/S2 is an evolution in looks…and a leap forward in performance.
I don't think there's much of an economy difference between the 2...So, if I wanted long wear in commercial service, the A/S.
If I wanted good all season traction and a smoother ride on the highway, the MS/2. You're in Toronto...and that MS/2 is designed for good snow traction...
The MS/2 is a great tire, you can't go wrong with it.