I haven’t used Manjaro myself but I heard that it is not as good as Arch. Rumors I heard where that it is not as solid as vanilla Arch. YMMV.

Which one(s)

Arch.

why?

1. The Arch-Wiki
2. I like pacman
3. The Arch-Wiki
4. I wanted a rolling-release distribution.
5. The Arch-Wiki
6. It just works. I had only one more serious problem in ~8 years of running Arch
7. Did I mention the Arch-Wiki?

Edit:

Having said that, I have an eye on immutable distros. Maybe one day I’ll try one out.