Dear Blick, X-Air, and WeatherCat sys-admins,
My experience has been a little different than yours, Edouard. I am running Yosemite on all three Macs at our house and I like it. It's tight integration with iOS is very helpful.
Alas, my experiences are indeed very different. This morning I was simply trying to get Spotify up and running for the day's music and my MacBook Pro had a kernel panic. It took a second reboot to finally get my computer running again. When I was running LINUX this simply -
*NEVER* - happened. Apple has really taken out the robustness of the UNIX heart of OS X and that's just inexcusable.
Moreover, I see Apple doing something I really resent. Apple isn't simply shaking up the lives of end-users, clearly Apple is pushing hard to force developers to change. That's giving them effectively "busy work" and some developers would rather quit Apple and concentrate on other business. In the old days, this was Microsoft's stock and trade and was part of the PC industries game to force you to upgrade your computer. Of course, if the software title you were using was canceled - tough luck.
When Microsoft did this, the carnage wasn't as bad. Where was a software company going to make more money - on Mac? However, the Mac is still very much a minority in the computer world, so companies can punt on Apple and still make a living. So a number of software products that I really depend upon have been abandoned and I'm hopping mad about it. Apple's own spell-checking infrastructure cannot hold a candle to SpellCatcher and given that the main developer died after a brief battle with cancer, it is unlikely this program will ever come back. In a case like this, I think Apple has enough cash to pay for the good ideas of a developer how has fallen and give every Mac and iOS user a first-class experience when creating text. How Apple can be so backward about something as fundamental as creating quality prose . . . it really should worry us all.
"LeBrea", as in tar pits?! I'm thinking that will not make the cut for any future Mac OS. Maybe that other major OS...
As far as I'm considered OS 10.10 -
is -the La Brea Tar Pits of Mac OS. I just hope nothing Apple ever releases in the future is worse!

Edouard