What do you guys think? Should I make the jump - or stick with the 129?   90% of my riding is ON trail - off would be a few fields and lakes.

I have Cooper Discoverer SRX tires on my older Sierra Denali. Great summer tire rain or shine. Quiet, smooth, great traction and wears well.  Drove it to Florida in December a few years ago and it rained for 12 hours straight and never had an issue. On the way back in January, it worked well in the snow and slush from the Smokey Mountains and north. That was my only "winter" experience with them, (note: the Denali is AWD) and I felt confident. However, I do run winter tires so I can't give you an honest opinion on ice/snow capability.

I bought a set years ago for I believe our jeep commander at the time or maybe my Dakota - they were not good from a wear perspective on that vehicle.  don’t recall how they performed, it was a while ago. 

Turns out the Michelin ltx m/s has been discontinued.   Now I’m looking at Bridgestone duelers ascent. Any experience with them?

BRAAAAAAP