I'm an Amerikkkan. I listen to a lot of music from all over the world, Japan included.
I'm a big fan of so-called "New Rock", which was the result of American psychedelic rock influence in Japan, characterized by bands like The Mops and Flower Travellin' Band. It really does seem to me to be uniquely Japanese in character; it reflects the situation of Japan in the late 60s/early 70s, and a lot of it draws from classical Japanese music. At the same time, the influence of American hard rock bands like Deep Purple is very clear.
It's hard to really say what I "like more", but I do count FTB as one of my favorite bands of all time.
I've seen a couple of Japanese groups in concert - ALI Project, Polysics, SCANDAL. It seems to me a lot of Japanese bands have a keen sense of showmanship which is lacking for a lot of American bands. I didn't know anything about SCANDAL when I first saw them (it was a double header concert with ALI Project which was what I was mainly interested in), but I became an instant fan after seeing them - it's so rare to see the sort of stage presence they had nowadays.