I know I should try the betas, but I'm just going to wait for the final product, once all the apparently horrendous bugs are worked out. That being said, I'm still curious as to how this OS is going to run when fully released. When I first jumped from Mountain Lion to El Capitan, I thought it seemed pretty much as responsive as Mountain Lion. (This was on my 2006 Mac Pro w/ El Capitan workaround and an SSD.) And, now, with a 2009 Mac Pro, I've found it obviously even more responsive... but that still doesn't cut it. After going back and using Mountain Lion on the 2006 Mac Pro (old clone on some old, clunky HDD), I realized how much lighter the UI is. Finder, for example, opens as quickly as a hidden Text Edit document, and System Prefs opens instantly - and this is with a poor old HDD. Go over to my 2009 Mac Pro, with El Capitan and two SSDs set in RAID 0, Finder has a delay upon opening, and the menus in Finder are just choppy in general. System Prefs opens pretty quickly, but not in the instantaneous way that it opens in Mountain Lion. All of these smaller UI animations and general system tasks are just plain SLOWER. What gives? Do I seriously have to have a PCIe-SSD to bring up a Finder window like it should? And I doubt that, even then, it will be as quick as Mtn. Lion brings it up - on an old HDD. I'm waiting for Apple to hopefully get their stuff together and fix this mess. As much as a despise Sierra for being the bane of several capable Macs' existences, I'll be interested in it - BUT only if its UI is efficient. If I had my ways, Apple would still be on Mavericks, for crying out loud.