I’ve been using Nextcloud since version 13, and I’ve never even had one catastrophe. I’ve installed it on a Raspberry Pi, a Nanopi Neo2 (with an attached SATA drive), a VPS, and a QNAP NAS appliance in a VM. It’s been stable for me the whole way through.
Note: Contacts got sketchy on me a few times (accessing them through both CardBook in Thunderbird, and through DavX5 in Android), but I was able to fix it each time, as long as I took my time and made sure all the contacts were sanely entered.
I want to especially thank @nachoparker for his outstanding work, which made it easy to install on the ARM boards (this man pretty much deserves to be worshipped on sight), and all the Nextcloud devs (@jospoortvliet pretty much also deserves “worship-on-sight” treatment).
I use Nextcloud Files, Contacts, Bookmarks, Notes, and News the most. These are part of my daily routine, pretty much, and I rely on them. No Google services for me (other than the bare minimum I need to scrape by with in the Google Play store on my phone).
Thank you everyone, who has helped Nextcloud in any way, including the great and helpful people on this forum.