I recently upgraded from Lion to El Capitan (10.11) skipping Yosemite on a Pro laptop and a Mac Mini, both 2012 vintage.
No problems so far with Logic X (10.2), Reaper 5.1, Lilypond 18.2. For command line apps, notably Enthought Canopy Python, I needed to fix a couple of issues in my .profile + /.bashrc.
Overall performance seems slightly improved, but that's a subjective impression not supported by any before/after benchmarking.
