Well I haven't been keeping up much. I finally had a Stihl fs 80 break down after about 8 years (first failure of a Stihl product). Have the 4 mix models proven themselves. My dealer still has plenty of fs 80 two strokes but I'm looking at the FS 110 r. Just not sure how many of you have had valve problems. So is it worth it to go to 4 mix now or stay with the good old reliable two strokes? Please note any problems you have had other than the valve adjustment. Thanks!