What do you think about Debian as desktop distro?

I've made mixed experiences.
Pros:
-Convenience without taking away the user's freedom
-large repos
-different versions (stable, rolling)
-runs nearly everywhere
-completely open-source

Cons:
-Rolling repos can be quite buggy
-stable only get security-patches and bugfixes, no feature updates
-apt can sometimes be a pain in the ass

In the end, Debian is neither the best, nor the worst choice, at least in my opinion.

An advice from me,
If you want to use the rolling-repos,
First, install your hardware drivers from stable, and make sure, they don't get updated from testing or unstable.

I use it wherever I can (Desktop, NAS, Raspi&Co, only my router has no Debian and runs on DD-WRT).

If you need the latest stuff, you should go for a more up-to-date distribution, or you'll be forced to install too much manually.

And you should keep an eye on the right hardware. Unsupported hardware is a PITA (but that's true for all linux distributions).

What I like most at Debian is that it's stable, not only the software, but the whole project.

Its "character" hasn't changed much since the first time I came in contact with it in the late nineties. Debian is still Debian, whereas many other distributions have massively changed or even disappeared over time.

If you plan to stay with one distribution, Debian is definitely the right choice.

I am no expert in this but in my recent quest/search I have found Manjaro to be quite interesting.