Love my MS2's. Have 26k on them right now and they still look almost new. Quiet, smooth and great in the winter for me. You pay more for them, but they last longer for sure.
for a michilin tire those cracks are normal ive had a lot of customers come in with 1 yr old michilins that looked just like that or worse they wear like iron but the cracking is very common
I am no expert with tires, but I would not trust my life or my family's lives with a tire that looked like that. I have seen two blow outs on the interstate and the results were not pretty.
My tires have looked like that for years, that is just the outer rubber. I only put about 2k miles a year on my truck so replacing tires that crack would be replacing new tires for me.
The cracks plus the the age plus a vibration even after a balance made me decide to replace them. At 6 or 7 years old next time, the M/S tires should be prety close to gone. The new ones give a nice, smooth, much more of a cushioned ride.