I believe most of the times it was: Oroooo... ? xD Hehe, I definitely need to find some more time to finish the series... But, it's definitely a hidden gem of anime. It can easily stand on its own against the supreme computer/+CGI modern animation.
Nah, unfortunately I haven't. To be honest, I recently became interested in watching anime as a whole. I learned about R.K. by pure luck! (I found the first volume of the manga on my language literally at a store in the middle of nowhere)
So, I looked it on the web and saw all of the critical acclaim it had received, I felt I had to watch it. It certainly had that nostalgia of the classic 90s anime, the aura of differentiating a masterpiece from a modern rated 8.5 anime. But, I will definitely check the OVAs (I believe they're prequels?) when I'm done with the main series