That may be so but honestly the last release of OS X that really worked for me was snow leopard. Just as a quick list of common well known issues with Mavericks that I have and I'm not the only one to have...
- Sometimes when I plug in my headphone, there's a bug and audio stops working instead of switching to the headphone. The only fix I found is to restart the computer.
- I'm using a macbook pro retina with 16GB of ram and mission control slows the system to a crawl whenever I want to use it. Expose just worked on a computer with 4 times less ram and vastly less powerful.
- Sometimes when I connect an external screen, the computer just crashes completely.
Honestly, I just wish Apple would start actually doing some QA and fix those issues... The machine itself is great and powerful but it's really a pain to have to deal with all the bugs. And I say that not as an apple hater (all of my computers are from them except my server).