After installing the last beta of 10.13 High Sierra on my unsupported MacBook Pro, I am happy to report that I am quite pleased with the new OS. HS is ready for public consumption, at least for end users like me. It also feels fresh and performance is decent. If your computer ran El Capitan fine it should run High Sierra fine too, assuming it’s supported. And even if HS Sierra is not supported, it may still run fine if installed with a patched installer, like in my case. Even 4 GB is acceptable for light usage, but I’ve upgraded to 8 GB for more breathing room on this MacBookPro5,5. I also have SSD with TRIM. Yes, performance isn’t great on a HD but it’s no worse than HD performance on El Capitan. I will be upgrading my 12 GB 2010 27” iMac Core i7 with HDD as soon as High Sierra is officially released. Also, I will upgrade my more recent machines quickly too, and that includes both a 24 GB 2017 27” iMac and a 16 GB 2017 MacBook. You might ask, “Since El Capitan or whatever is working fine, why bother upgrading?” Well, IMO High Sierra is a major milestone in macOS’ evolution. It builds in new file format support so if you don’t have that support you are going to be left in the dust pretty quickly, esp. if you’re using modern iOS devices. The only issue I can’t comment upon is encrypted Apple File System support. Some people have reported issues with encrypted APFS volumes on Macs, but I don’t encrypt my Macs. Note that iDevices already now use encrypted APFS though, and they work fine, but that’s a more controlled environment. Overall, High Sierra is great. Highly recommended.