I used to watch a lot of Japanese things - Jdrama, Anime... but currently I prefer Kdrama. Perhaps I find it a refreshing change of pace, or I'm just leaning towards romances right now, but I find that they tend to grip me more. That said, it's really a mood thing. It's the same with music, I listen to Kpop most of the time but there are moments when I just want something with a bit more "bite" and I turn back to Jrock.
Mm, overall though I'd say Japan/Japanese stuff (aka drama, etc). There is greater variety to their drama and the culture interests me more. The only thing I really prefer from Korea is the music.