It is soooooooooo nice to be back on Ubuntu. I appreciate the people that like and develop Arch linux (and especially anyone that contributes to the wiki is a true hero), but it's not a good distro for your daily driver:
1. "immature" packaging. It's crazy to me how much manual intervention is needed during routine package upgrades. This can be major break-your-system stuff (they have a mailing list for those types of changes so make sure to subscribe), or just stuff that could be done for you but isn't (like updating your db during postgres upgrades).
2. Tiny official repos. You're going to have to rely on the user-submitted repos for most of your packaging needs. It's cool how easy it is to make a package and submit it to the AUR, but I don't love the idea of installing random user-submitted stuff for the bulk of my software needs.
3. No debug symbols. Maybe this doesn't affect most people but it is very annoying that there is no (convenient) way to get debug symbols for a package /lib. If a program crashes on you and you want to fix it, the official solution is to rebuild a package (and all its dependencies as necessary) on your own system to get debug symbols. In contrast, ubuntu/fedora/etc. will install a debug symbols package for you (automatically, I think) when a program crashes.
In terms of learning Linux fundamentals: arch could teach you some things (LFS would be even better--but I wouldn't sue either for my daily driver when better options exist.