We have 60 Macs (Mac Pros, MacBook Pros, and MacBook Airs) purchased from 2011-2015. We see all the problems mrmondo mentioned except the iTunes one (we don't u

We have 60 Macs (Mac Pros, MacBook Pros, and MacBook Airs) purchased from 2011-2015. We see all the problems mrmondo mentioned except the iTunes one (we don't use iTunes). The true deal breakers for us, though, is the terrible Wi-Fi performance. The Macs get spurious Wi-Fi failures; all Windows, Android, and iOS devices work fine on all our wireless networks. As a result, about 45 of our Macs now run Windows 7 or 8. That means the users get a worse UI and not nearly so much functionality built in -- with the tradeoff being that the machines run predictably and reliably. It seems everybody now has their "back in my day..." OS X version when things were stable; for me 10.7 was the last good version. All our problems started with 10.8, and things have been going downhill since then.