While I would agree that the main problem is Safari, when I downloaded Yosemite on my Mac Book Pro, other functions were also sluggish---certainly not the lightening speed Yosemite promises.
Additional factoids I've found:
----First, Yosemite continues to work flawlessly on my i-Mac (circa 2010). Ultra-fast speed and all other advantages Yosemite promises.
---I recently replaced my old Mac Book Pro 15" with a new one. When I talked to the sales person, I was told Yosemite was pre-loaded. However, that was not the case on the 15". It still had just Mavericks 10-9-5. However, the smaller 13" versions had Yosemite. Now I suppose this could be due to the timing of when these new units were built (compared to the final release of Yosemite), but it also raises the question of whether this Yosemite problem is unique to something in the 15".
Has anyone had this problem with Yosemite who owns a 13"??
When purchasing the new Mac Book, I had some other problems with the sale, but happened to raise this issue with the rep I spoke with. They knew nothing about the problems we've all noted. I was told Apple Tech department does monitor these chat threads, but that still begs the question of when will Apple step up to the plate with a fix. For the time being, I'll hold off loading Yosemite on the new Mac Book Pro 15"