I doubt there is any introduction to German Linguistics that is truly interesting. Busch and Stenschke's at least requires not a pinch of knowledge beforehand, which was a true lifesaver for me, who never cared about Linguistics. The exercises in the book are doable but also make clear that for a proper understanding of any of the different topics, one needs quite a bit of additional texts and theories with more depth. I will try my luck with Bross and Meibauer next and see if I will understand the deep-dark layers of German Syntax. Things I never wanted to know and doubt I ever need again, but here we are.
What I like: The exercises, the straightforward approach Badly Done Is: The mediocre quoting of different theories without dividing them properly