Arch Linux. Many people said it is unstable and hard to setup. It turns out very stable as long as I update it frequently and AUR makes installing software easier. Even easier than ppa-based ubuntu as it will destroy your dependency if you are not careful. Lol.
Almost. But with one key difference. PPAs are precompiled binaries where you cannot inspect the source - you have to trust the maintainer of the PPA. AUR is a repository of source packages which you can download and inspect yourself (or hope others have done this). This makes AUR more community focused than PPAs I feel. AUR is also a central repo managed by people that dont own the vast majority of the packages hosted on it and where packages can be taken down if found malicious. PPAs are lots of separate repositories all managed by different people that generally maintain all the packages for their PPA.
Though in both cases anyone can upload anything to them, so they are not 100% trustworthy. But I do think the way AUR works puts them ahead of PPAs.
Also you can't just install these packages, you have to import the keyrings of any packages that access the kernel. That requires you to go to the website, check out the owner of the key, see their contributions and decide for yourself if you trust it