I'm going to necro-bump this threat starting now....
Mavericks was free, in my opinion, as a reaction to Microsoft releasing 8.1 as a free upgrade to the masses that were already running Win 8.
For me, Mavericks as been nothing but trouble. At work, my displaylink drivers were shit until new ones were released.... something that can be forgiven, except that the build has been available for partners for MONTHS. Beyond that, I can no longer use my mouse and keyboard as their functionality has been completely jacked since updating. If I use any secondary pointer device, something other than my built in track pad, I have an unusable experience. I can't use my performance MX mouse because it will just stop responding on clicks randomly... mostly when I switch monitors on my multi-display workstation. I initially blamed this on Logitech not getting their damned drivers out but when trying on my Apple magic track pad, I get the same damned behavior. This is an Apple problem and I have reported it twice already. Here's hoping they choose to fix these issues soon, rather than later.