Don't base your decisions on one person's experience.
I've pretty much used all Apple hardware and all versions of their Operating Systems from the Apple SE and OS 7 onwards.
There is nothing wrong with Mavericks.
Mavericks seems a rushed attempt to make my desktop slightly more like an iPhone
Mavericks doesn't make anything look like an iPhone ! It looks, feels and behaves in a very much similar fashion to its predecessor.
Color labels are gone from Mavericks, which surprisingly is a big disruption in workflow in the Finder.
Weird workflow he must have. Spotlight is so good in Mavericks that you don't need to go searching around stuff based on label colours. If you really feel the need to go beyond Spotlight, Mavericks has tags and you can search for tags.
in order to preview all kinds of video files on the desktop level without having to convert them firs
Really ? Sounds like nonsense to me. Anything quicktime can read you can preview easily by hitting the space bar.