Slow boot is very much a high sierra issue for some (actually more like a lot), not just an issue. People in this thread, while enjoying picking on the OP seem to forget than High Sierra has an overall weaker, or slower performance than Sierra and previous versions. It's not just about the "slow boot". This is happening on a supposedly much modern and faster file system, with a more "refined" and "optimized" OS. If they're ok with that that's fine but they should stop pretending high sierra is "better", it's not. I really didn't like downgrading as it took me a lot of time to have everything properly reinstalled, but Sierra just feels right. What major functionality makes HS a 'must-have' upgrade? None. If HS represents a more streamlined Sierra, then why is it slower? Should be the opposite, regardless of the hardware. El Capitan was, for me, the last time an OS upgrade felt like an actual upgrade (better performance, better system font than Yosemite, etc). But useless background processes also started to pop up, which got a little worse with Sierra, and even worse with High Sierra. Sadly I don't expect much from the upcoming 10.14 either.