Dir En Grey is pretty popular here in the USA (for a Jrock band). Where I live, they usually pack where ever they play (not necessarily sell out, I don't think). I saw them in 2006 and the place was jammed. Also, I saw Exist Trace here a few months ago and there were about 50 people there. So, I think a lot of it has to do with exposure, but not all. Rammstein sells out here, and they are German. I think Miyavi did really good too. I think SCANDAL isn't that known (I don't know anyone here who heard of them). Dir En Grey I know a bunch of people and more for Rammstein. I think it's much easier for American artists here to go to Japan than it is in reverse. Which is sort of a shame. Well, except Hawaii and California. They seem to get some good bands/groups.