The AUR community packages repo (with Yaourt tool) is definitely the biggest draw for me. It has basically everything you'd ever want as a linux desktop user, whenever you come across a program online it's almost always already available in AUR if it's not in the main package repo (which often mirrors Debians package availability).

A common issue with Debian style distros is that you can install packages easily but it often comes with lots of configuration afterwards. It doesn't "just work"

AUR community scripts are like APT but for less popular programs that aren't supported in the main repos and, more importantly, packages that come with more complete installation scripts with necessary configs and supporting tooling.

Like any OSS community it's benefited most from a lively active community.

ArchLinux is easily the best experience you will find for desktop Linux usage. Plus the Wiki is the best around for Linux.

It's the only distro where using GRSecurity is as simple as installing a package. That's just not possible on Debian.

I'd still use Debian for servers as most VPS companies don't support ArchLinux natively, the set-up process for Arch is a bit intense, and if anyone else needs to get access it's better for portability.