What offer debian that arch doesn't offer?
Arch it is really stable and with latest packages. I see debian as a pain in the ass when you want a new packages or you have to upgrade to a new version. I don't have those issues in arch.
I think pacman is one of the best package managers. And as I said, arch it is quite stable, a little less than debian, which stops me from using it in production, but good enough to use it daily.