arch linux is a popular, independently developed GNU/Linux distribution which follows the rolling release model. arch linux is known for the "arch btw" meme on linux meme subreddits online, and also known for being broken and shipping untested and unstable packages.
1. you want a painful and stressful experience with GNU/Linux
2. you want to fix all your stuff by yourself
3. you want a "minimal" systemd GNU/Linux distribution
4. you want a very large repository of software (but its not trusted), called the AUR. we will get to it later
now lets get to my experience with arch:
so arch linux isn't really that bad, it is actually not bad, but also not good. the real problem with arch linux is it's unstability, and the arch community tries to make up excuses for that, such as "arch is DIY, cope" and similar stuff. arch would actually be a good distribution if it was more stable and the packages were tested before releasing them. my actual experience with arch was good, but i had some stability issues, for example some packages would break when updating.
AUR stands for the Arch User Repository, which is arch's own user repository with a wide selection of packages maintained by arch linux users. the AUR is the real reason why would a sane person would use arch, maybe you want to use some software which isn't available in other distribution's repositories (in this case, you should compile it instead of installing a whole distribution just for installing it). the AUR isn't also all just pros, it has its own cons, such as being maintained by untrusted users who may release malicious packages/binaries, some packages are also unstable and untested, and a lot more to list here.