got mine yesterday, i too ordered the day it was announced, but not played as i took my daughter to the seaside for the first time yesterday so the 360 took a backseat

just opened the box, and i have to say build quality is pants
i reckon if you're a bit hamfisted you could damage either the HD or the 360's HD slot
took me a good 10mins to marry it up properly, but once connected it works fine, which i guess makes up for its shoddy workmanship
once on, i'd leave it in place tho, as i think repeated removal/attachment could make it worse
having said all that, it does exactly what it says on the tin, so its time to poke about on my HD

PS. the lovely blue glow on the advertising pics does not happen, coupla little LEDs on the back end set to glow thru a serrated plastic piece that runs down the side, the effect being you get light at the back & a bit at the front, so i think i'll replace those with green ones to fit in with my standard 360 (surface mounts are toooooo small for my old eyes to replace on the 360 itself)