I found this forum thread for you on another site and it seems to have a good rundown on the differences. Hope it helps!
IMO, I swap out noodles all the the time in my cooking since my closest grocery store has a limited Asian section, and I don't always feel like driving the extra distance to the closest Asian supermarket. Sure, it might have a slightly different texture and flavor, but dishes usually taste just fine no matter which noodle you use. I'm no purist. :P