i'm not familiar with sc.d or eng.d or whatever, but i'm assuming they're much more difficult than a ph.d. to get a ph.d, you pretty much do a shit load of research in any area. at least, i could get one in psychology if i worked long enough on a thesis and etc. sc.d and eng.d are short for science and engineering probably (fuck you i'm not googling that right now). science classes, in my opinion, are MUCH harder than the average college course. if you got the brains, put in the extra effort
not that a ph.d isn't worth shit, i just think the science aspects would be seen with more, prestige maybe? kinda like the difference between a ba and a bs.
however, i could be a million miles off