This is very beautiful, albeit busy. The details is all perfect, too - all the line work looks balanced and neat. Very well done! must have taken an age.
The only negative, and it is slight, (and ironic) would be the top right corner - I just feel that the white space there isn't balanced properly. I mean, almost like a fractal, it's growing.. but I personally would have liked to see that pattern reflected in another part, or a balance of dark space (see? negative, lolol) somewhere to balance.
4am rambles. Not a great comment, but a great pic.