Yokohama are a really soft rubber and mine wore down after one summer of mountain killing. They were very good but got a little loose sometimes. I then had Kumho which I dont mind at all and they are a quality and reliable tire. I am currently running conti's and I hate to say it but they are my least favorite of the three. They tramline and are uncomfortable and I dont feel that I get a very nice grip at all at high speeds.
For the record, I was running 45 YOKO and KUMHO and am at a 40 Conti so I know that is a factor in my displeasure with them. I got Conti's because I have heard many great things about them.
Theres my tire story.