I also listen to BM since I was...maybe 12? So 15 years and counting
Even now I mainly listen to bm (well almost always)
When I got a bit older I have start appreciating other geners. That can be rap, electro or even J-pop I really dont care. It's not like when I was kid "metal or nothing". Ok, I dont listen to whole discographies but there are some songs that are really catchy. I love good soundtracks from games/movies like akira yamaoka and mary elizabeth mcglynn (silent hill) or black mages (final fantasy) or good electro like Ice ages.
Anyway, if something is good and I like it I will listen to it no matter what gener it is