Great system as far as I am concerned - even if I tend to use KirbyCMS for most of my projects.
There aren't a million dev adopters, but I actually see this as a benefit, because if you talk with someone from the forum, you'll see that most of them are highly experienced engineers. Core team members are in the US and EU.
even have built some complicated apps with it with great success.
it was the first headless CMS I found, before headless was a thing.
Just keeps getting better all the time too