You can check their debut and older performance before gee era, they were pretty good. If you're not lazy, i guess they have ballad performance too but i don't remember what video but it definitely showcase their voice.
Wow. I would not have got a single word without the subtitles. 'XD But I think out of all three languages, this one may be the one I like best, so it's rather a good surprise, and the performance was OK (not enough live singing though, too bad). Thanks a lot for sharing!
their other japanese versions of korean songs were better (for example i dig Gee a LOT more in japanese, even tho i listened to the original since it came out)
and i'm disappointed that they only do the korean version live