Ok, I'm posting this because I witnessed exactly the opposite result of installing High Sierra that I was expecting, and wanted to see how many others may have experienced the same issues. Once I upgraded my 2tb SSD with High Sierra GM (from 10.12.6 Sierra) from a cold boot the startup time went from 27 seconds in Sierra to 44 seconds in High Sierra. The progress bar seems to stall for quite a while around 2/3 the way through, then finally progresses. Equally concerning, everything I heard was that after the High Sierra install, I should see some space (maybe not lot but some) freed up. Quite to the contrary, right before installing high sierra I had 465.61 GB used on that partition. AFTER the install of high sierra GM, there was 482.56 GB used. So just by installing High Sierra I LOST around 17 GIGS!!!! And yes, it did update the file system from HFS to APFS. Anyone see this with their installs? And if so, anyone have an explanation (or better yet a solution?).