Octopi has always been the only thing worrth recommending because its exactly what pamac and shelly are not - a frontend for the official package manager pacman.
And more sprinkled about.
While those quotes are all from before shelly existed nothing has caused me to fundamentally change any of those positions.
And still thats just for the GUI folks.
pacman (and paru if you need an AUR helper) are mighty fine on their own. 