Easy to use, and as cutting-edge as you want or as stable as you want.
Very user-friendly, and Manjaro IS famous for its superb hardware detection.
As suitable for old Linux hands who want a quick-to-install Arch experience, as for total beginners who only want a computer that just works.
Not too many; some AUR packages don't compile at all, and I have, using pamac, had to use yay to install the dependencies pamac didn't install first.
Pamac is quite inferior as a PM to Synaptic, I must say. It's not terrible by any means, though.
And these are Arch problems, not Manjaro problems.