Interesting! That reminds me, the people I know who learned Latin in the US in a religious context learned the ecclesiastical pronunciation, the "Chi-che-ro" one, but everyone I know who learned it in an academic context learned "Ki-ke-ro."

Even though it's apparently hard even for native speakers -- I read somewhere it's among the last sounds children manage in languages that have it.

Lol, I needed a year of speech therapy as a child just to manage the English 'r' (along with 'ch', 'sh', and 'j').

But I think German is quite forgiving with Rs since you can do different kinds and they're all allophones that will sound okay.

You might think so, but have you ever tried being a non-German speaker asking for directions in Germany? In Berlin, my wife tried asking someone how to get to Neue Grünstraße, and the guy--who, surprisingly, spoke enough English to understand the question and give directions*--needed her to repeat it several times before he said, "Oh, you mean GRRRRRünstraße!" with a German 'r'. It's not easy!

* She agrees with me that finding such people in Germany was difficult, contrary to the perception of German speakers who speak English well enough to tell us that everyone in Germany speaks conversational English. ;)