Hmm, there's surprisingly little in there if you don't have (or want) an iPhone. Is it time for us that don't want to use (and only use) Apple devices to shop elsewhere?
It's free, adds lots of stuff in the backend (libs etc), it's the default version from now on (the one with all the new hardware support, security updates, etc), it fixes several bugs from older versions (and of course will introduce some new of its own, nothing is perfect), and for those "without an iPhone" it has better voice control, tabs everywhere, new Messages and Photos app, updated Mail app, and a nice Cloud integration to save you space, with on-demand transparently downloaded files.
OS X is not like some third party program that works for decades and you decide whether to bother to uprgade to the next version or not. It's more like modern browsers: it's evergreen and you're supposed, if your hardware supports it, to be running the latest version.
