It's a single go executable that's much easier to install and keep up to date. It's been a while since I've used pihole but Adguard Home also had a better GUI when I first started using it.
For me the main reason to switch to AdGuard was that it can easily run on OpenWRT (and PiHole can't). It's really convenient to run DNS adblock on the same device as your router.
The openSUSE build system is also great for building packages for a lot distros. It's not just for openSUSE.