I came to resent their marketing blog posts. If you look it's just an alpha version that just got hacked together, often with problems, often not fixed long after the release. There still lot's of serious bugs in end to end encryption for instance.
There does not seem to be a lot of work to improve the base features. Syncing, ACLs, User Mangement leave a lot to be desired. It's not easy but they are in a position where they really could be a perfect solution for a lot of people and probably also charge good money for it - but at the moment it feels like they just build alpha-grade fancy addons.
Me and probably most users would love a no-feature, we just fix the most serious bugs on our github issues release-cycle. I'm fine when it's called Nextcloud 16 and takes a year, hell take your time, but basic functionality should be rock solid.
I also don't get why they ignore the existing open-source ecosystem. Make it possible to integrate SOGo for Calenders and Mail - it's all webdav in the browser anyway. SOGo at least has somewhat working ActiveSync. Same with SAML/Shibboleth/Kerberos - some things got fixed, very late. No deployment story for Active Directory or even Linux.
User management is a mess - the Circles app is a good idea that is crippled by usability and functionality bugs... that possibility to have self-selecting groups and decentralized management is a huge win for them, but they don't seem to realize that this is an important use-case.
Nextcloud is very close to what would be ideal for a lot of smaller organisations, but they somehow are unable to polish what they have but decided to pile alpha-quality on alpha-quality code (and ignore the bug reports)...
That beeing said, it mostly works but your users won't be happy.