I use a mid 2014 rMBP (2.8/16Gb/1Tb) all day long for work. Finally I had enough of El Cap and its crummy performance, stupid gimmicks and dumb design decisions. Backed everything up one last time, wiped the drive and installed Mavericks 10.9.5 What a relief to have the super snappy computer back. Of all the software I use, only Microsoft Office 2016 will not run on 10.9. (Oh the irony). Microsoft you can go and sit on the naughty step with those other idiots VMWare and Parallels - forced upgrades with no benefits are no longer acceptable. Don't get me wrong it isn't perfect, but if El Cap was 10.9 and Mavericks was 10.11 I think Apple's reputation on OS X would be a lot better than it is. Look up the El Cap User ratings in the App Store - shocking. If El Cap works for you, then that's great, I'm really happy for you. No, I didn't install El Cap "Wrong" and yes, I did know how to configure it properly. Apple took a decent OS like Mavericks, polished it up a bit, crippled it and delivered no benefits of note at all. (Like they did with iOS, but that's another story).