If you don't mind me asking a follow up:

How behind Ubuntu is Debian, and where can I read this information myself (i.e. is there an official list by either the Debian or the Ubuntu people that says "here's all the stuff that the latest stable Debian is missing from the latest stable Ubuntu"?)

It is not behind all the time: it just follows a different (and more flexible) schedule. [1]

For instance, the current debian stable release entered freeze on 2019-01-12 and was finally released on 2019-07-06. [2]. This means that most software in stable is currently at the latest versions as of the end of 2018. Hence, up until the release announced today, debian stable had more recent (by around 1 year) software than Ubuntu LTS (18.04).

Now and until the next debian stable release (which should happen around summer next year) Ubuntu LTS (20.04) will have newer software than debian stable.

There are a few software packages that do have newer versions in Ubuntu because they are developed by canonical themselves. I can only remember LXC/LXD as examples of these.

I personally run Debian on my personal Desktop, and have no complaints about it at all.

[1] https://wiki.debian.org/DebianReleases

[2] https://release.debian.org/buster/freeze_policy.html

how well do ppa's work on Debian?

I don't like my system constantly updating (and occasionally breaking) - esp secretly behind my back like snap/flatpak

but occasionally I do need the latest version of some package and i don't want to manage manually installations tucked away in some folder with random bashrc tweaks

There is no official support for PPAs on Debian. You can configure a Debian system to use them, but you'll be installing packages built on and for Ubuntu, so you'll be risking breakage unless the package maintainer has already taken the extra time to test for problems on Debian (which is rare).

This feature request shows some community interest in Debian support, but as far as I know, it hasn't gone anywhere yet. https://bugs.launchpad.net/launchpad/+bug/188564

I wish Debian offered its own equivalent of PPAs.

Damn. That's a real shame. I really like Debian otherwise. It's still minimal to the point where you can understand all the pieces. I used it for years, but then 5 years ago I moved off of it just because it's so easy to get software from PPAs and b/c every instruction is Ubuntu by default. Over those 5 years being a little flexible has ended up saving tons and tons of hour. Even just the other day I wanted to install OpenJDK 14 and ended up having to do it manually. Maintaining that in some directory and having my own update-alternatives entries.. it just feels really yucky at this point

In my experience, most software offering PPAs also offers debian repositories that get setup in your /etc/sources.d/ (usually the install instructions are just to run "curl https://somesoftware/installer.sh | bash", which you should doble-check of course). Thereafter your regular apt-get update && apt-get upgrade updates that software too.

It is really not an issue in my experience. I currently have the following software installed (and updated) this way: docker, virtualbox, nodejs, yarn, skype, vscode, teamviewer and sublime text.