Earlier quoted context omitted.
On the other hand, updating my Mac to Yosemite turned it into a slow stuttering mess - WindowServer memory leak forced me to reboot the Mac about every two hours or so or watch my desktop at While Windows does have problems, latest Apple software is mostly worse bug and update-wise.
Updating my iMac to Yosemite fried the graphics card. It seems Apple is putting form way ahead of function, and as a result stuffing too hot components into too small space (the same iMac has previously fried the screen and the HDD to death).
And it was easily solved! Apparently Apple (the rumor is Jobs ordered this, but who knows) didn't want the fans spinning too fast, which caused noise. So they governed the speed on those, too. Solved with SMC Fan Control.
I wasn't too happy about being somewhat deceived by their specs for my equipment, even if they thought their intentions were "good".