My buddy and I each bought the Mountain Extreme 400's. My buddy had trouble with one of his leaking, within the first year. He did call Kenetrek, and they told him to send them back. Unfortunately he never did. But I do believe Kenetrek would have made it right with him
As for me, I liked the boots. I thought they were very well built, solid boot. However, my feet did not like them. I consistently had soreness on the bottoms of my heels. Also, the heel cup is quite wide, (I do have narrow heels), I could not get my heel to stop slipping.
Another issue I had is I could not get them tight enough around my ankle/calf. Making the boot sloppy around my leg.
Like I stated earlier, I think Kenetrek is a good boot, however if you have slightly narrow feet, and skinny legs, these might not be the boots for you.
chris <><