i just built up the x-fdd myself.

the brake-arm strap setup is nice; rather than like a coaster brake, where the strap bolts through the arm, the arm slides up into a clip in the strap. it has a quick-release clevis for the cable as well, so wheel installation and removal should be easy.

as rhm noted, there's absolutely no documentation, and little on the website; i had to email sunrace to make sure i was putting the brake-arm strap on the right side (nondriveside). a bit disappointing.

i used it for the first time yesterday. it's a bit spongy like the other drum brakes i've used, but works adequately. it's laced into a fairly heavy alex DH rim, michelin country rock 1.75 tire, with a diacompe tech77 lever on the other end. i haven't hooked up lights yet, but plan to soon. it's all hung on my slightly heavy-duty, soon-to-be porteur-style bike.