I would gave bought a Grainger for my HB JB build, but the string spacing was wrong for me. But I did get my Hipshot bridge from BTN. A lot of my Hipshot kit has come from them. Always had good service and when I got a duff tuner with a very stiff section, they immediately just sent me a replacement without having to send the original back, which arrived the next day.

I must say that the Grainger certainly looks machined whilst the Sung Il looks cast. One may have certainly inspired the other.