The first question will be about pi-hole so let me please copy/paste my answer from product hunt.
First of all, pi-hole is an awesome product and kudos to its devs for doing a lot. Before AdGuard Home launch it was the only viable option in this field. Second, we named this version "0.9" for a reason. A lot of new features are planned for the nearest future.
Notable features/differences of the current version:
- AdGuard Home has the same software under the hood as we use for our public AdGuard DNS servers (which are quite popular) so it is ready for the heavy load.
- Simple UI, configure malware/phishing blocking, blocking adult websites or enforcing safe search, all in a couple of clicks.
- It understands adblock rules syntax so you don't need 10k lines hosts files to block doubleclick subdomains.
- It shows you some metadata about domains, and it's quite interesting to see who really tracks you.
From the developer's point of view: AdGuard is built on modern tech and written entirely in golang, which makes the further development easier. It is not a set of different tools (like pi-hole), but a single binary - easy to deploy and manage, and it can be compiled for whatever platform you want.