Just echoing the other posters (bad pun), but the beige is the USA model and the black ones I think were made in Japan?
There's three types: beige, black, and the black SDE II. I've read that the beige and first black units are functionally the same. The SDE II adds a knob to control the input level, but I think otherwise is suppose to be the same.
I have a black SDE (not the SDE II), and I think it's great. I keep the high cut on, add just a touch of modulation, and use short repeats for always-on ambiance. It sounds great for longer delay, too. Kinda wish it had presets, but since one of the things I love about it is that it's dead simple to use, I can deal with it.