I couldn't got into j-rock so I gave up on it. I like several songs from JE's artists and that's it. Japanese girlgroups completely don't appeal for me (I think I need some recommendations)... I really can't find gems in japanese music which isn't a popular female singer.
I'm more into k-music obviously. Everyone has their own taste.
I try not to completely rule artists out, I even can give one artist one, second, third chance... At least I like one or more songs at last
There are some singers and groups I'll never like though. No matter if they have looks, charisma etc. music stays as the most important.