Sometime during late 2015, Apple will release yet another free and new system named
"El Capitan". I honestly believe whoever came up with that name must have been sniffing glue regularly as a child. I'm also beginning to suffer OS X fatigue as Apple has released a staggering 12 new operating systems in the past 14 years.
This is not a review of El Capitan, its simply generalized information that may be helpful.
First of all, this new OS is really all about improving the dreadful performance of Yosemite, which on a slightly older Mac that has been upgraded several times, is about as responsive as a three-legged pig when compared to earlier versions of OS X.....especially if booting from an external Thunderbolt drive.
Apple, uncharacteristically and candidly admits the new OS is primarily about improvements to system performance as opposed to must-have added features and new technology.
I've taken a look at El Capitan and although I haven't given it the full test drive, in fact, I probably won't until the final release, I can say who SHOULD and SHOULD NOT upgrade once available.
Those running Yosemite on a new system shipped with Yosemite installed are good upgrade candidates as your speed will most likely see an improvement. Also, those who have upgraded to Yosemite from Mavericks and have been disappointed with the lack-of-snap can also benefit, (maybe) from upgrading.
If currently using Lion, Mountain Lion or the older Snow Leopard, I would avoid it as the upgrade could prove more damaging than helpful as you might have to upgrade to at least Mavericks first, followed by upgrading to El Capitan, which can be messy and burdensome for your system, especially an older model. So, if deciding to venture down that path, make certain to have a full backup ready.
Here again, I don't quite understand the need to upgrade an operating system to a completely new version unless absolutely necessary. In today's environment, most do since its FREE. But just because something is free, doesn't make it the right thing to do.
On my older iMac, shipped with Snow Leopard, I continue to use it and have only updated to the latest and final version of Snow Leopard, 10.6.8 and intend to go no further updating this system. It can run Adobe CS6 products and Creative Cloud up to CC 2014. In my opinion, 10.6.8 was the most stable version of OS X to date and still commands about 30% of the user base.
My newer iMac, with Yosemite factory installed, I'll most likely update to El Capitan as there's an actual benefit in doing so, although will test the final release of El Capitan again first with an external SSD drive.
For those wondering, I do in fact download and install every new release of OS X, although usually never update the original internal drive beyond the final version of the base system. I only install new versions of OS X to partitions of an external Thunderbolt drive, mostly for testing purposes. But hey, that's just me.