I'll air my recent horror story: my Mac Mini Server 6,2 (2012) has two SSDs I had welded together as a RAID-0 array. I updated from 10.12 Sierra to 10.13 High Sierra without a hitch. On 20 November I for reasons I know bitterly regret I decided to wipe my system and reload from backups... an exercise that usually takes six hours, max. I've run into issue after issue (High Sierra formatting the RAID array as APFS by default and then announcing that is not a bootable configuration, terrible RAID drivers littering my installer log with write errors and thus refusing to restore Time Machine backups onto the array once I reformatted it as JHFS+, and latterly some obscure kernel cache error that precludes booting)... long story short, twelve days after the fatal decision, my system is still not bootable.
And Apple Support is non-existent. Documentation about APFS and RAID is thin on the ground. Phone support told me in no uncertain terms that my Mini's number was not a Server so I could not access Enterprise Support, and of course the consumer level folks do not know anything about RAID (or even multi-drive systems). It's been a total shitstorm.
Never have I been so proximate to just dumping them and telling them to piss off, but I also know I won't, because I am too deeply invested in their integrated ecosystem (macOS, Mac Pro, MacBook, iOS, iPhone, iPad, Apple Music...)... except I am starting to think it might make sense to tell them to piss off integrally and voting with my feet.