My friends are pretty ambivilant. But luckily my parents LOVE it. I basically forced it on them so much by always watching concerts and listening to the music that they started to like it to. But they became FANS when I showed them a subbed collection of Ayumi live performances. I showed them the songs that are typically Ayu's most powerful such as A Song For Xx, Teddy Bear, and Memorial Address. They loved the performances and lyrics so much that they are hooked on her now.(My step dad even CRIED durring Teddy Bear) So now, it's usually them asking me when Ayu's next concert DVD comes out and my Mom has been with me twice to Ayumi concerts. They also love several other J-POP artists as well now. (My Mom is pretty much in love w/ Gackt and Hyde and my step Dad wants to go to a MM concert and jump around with all the crazy Otaku.) So yep, they are big fans.
It should be noted though that my parents and myself lived in Japan for a few years on a military base, so they were already well accustumed and open to Japanese culture. So it was much easier to "convert" them so to speak.