Hi Raytops, The Ultimate Edition you have contains most of the original cut, leaving out, I think some great scenes, (I'll not bother listing them, I'm sure Wikipedia has the lowdown) plus a few scenes shot for the 1980 scene, namely the ship in the Gobi Desert and a bit more, but as you know, thankfully the "Inside the Mothership" extended ending is removed.
I've seen CE3K loaRAB of times over the years, and got really bored with the special ed. So when the Ult. Ed you have came out it was a breath of fresh air. But watching this original cut was a real treat, OK I geeked out over Blu-Ray picture quality and got a real sense of nostalgia seeing scenes I don't remember at all, I mean, I don't remember Carl Weathers in any other cut, and his scene is great. I may be way of on this as it's been about 4 years since I last watched it, but crikey, what a film. Even the whole whimsical take on the subject matter seems so relevant today, it's a real "they don't make 'em like that anymore" film, and The Beard himself is living testimony to that, but as I said times are so different now.........Christ! listen to me, I'm only 38.