Ever since I updated, which was the first day, my MacBook Air is running much much smoother. No more beachballs, no more just a general feeling of laggy-ness! I am very impressed with the result of OS X 10.11.4, and think this is what the El Capitan Golden Master should have ran like! Just my experience on a Late 2010 MacBook Air & 2013 MacBook Air. Let me know your positive experiences!