What are the advantages or disadvantages to using Manjaro instead of Ubuntu-based distros?

No, pacman is the package manager for Arch while pamac is the package manager for Manjaro, but both can be used on Manjaro since its based on Arch. There’s nothing like PPA in Arch AFAIK.

Manjaro already brings the latest software.

Aur is a repo/collection of packages(application, library etc) not a package manager. pacman works with aur.

For more info visit pacman and pamac.

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