Apple just launched the public beta of macOS High Sierra. It's available to download now if you're feeling brave (and enroll your devices), or you can sit back and let everyone else face the inherent risks and breakages involved in a new OS, then reap the rewards when the final version launches — presumably this fall. Also you can check out our preview of High Sierra while you make up your mind.
The riskiest and possibly most interesting part of High Sierra is the new APFS file system, which replaces HFS+ as the new default. In existing betas of High Sierra there's been an option to stick with HFS+ when installing, but otherwise your drive will be in-place upgraded to APFS. If this sounds in any way scary to you, you're probably best off putting High Sierra in a separate partition for testing, to keep your existing files and folders untouched. But Apple has already upgraded millions of iPhones to APFS with little hassle, so if you have standard Apple hardware in your computer it's probably a relatively safe procedure.
Other features of High Sierra include the Metal 2 graphics API, which supports VR and external GPUs, and the new HEVC and HEIF video and image formats which have also been added to the upcoming version of iOS.
Some of the handful of user-facing improvements include tweaks to Safari, Photos, and Siri. But this OS is really a foundational tech release, and unless you have a serious need to test out these new technologies and APIs, you won't be missing out on much by waiting for the official launch.