I would stick with the Michelin's. I ran them all last year on a YZ400 and they hooked up well and proved to be very durable. I'm also running them this year on a 300 MXC with good results so far. I'm running the S12's.
Not much new to add but I have been using S12's since I replaced the stock tires on my Kawasakis a year ago. I ran about 10lbs year round here in the Northwest and no pinch flats or complaints. I have never ridden in the Northeast but here we have generally moist soil and lots of roots an rocks.
I took them out to the Destert 100 (very dry with sharp rocks) and ran the poker run. The tire already had three races and about 100miles of play riding on them and the leading edges of the rear knobs were rounded over pretty good. The first 35miles they didn't look like they wore too much, the next 35miles I was really moving and they shredded pretty bad. The fronts are still in great condition.
My Gas Gas '01 XC200 arrives next week supposedly with M12's. I am anxious to see how those hold up.