Terpor: So which one is better, the VGA or the original?
I prefer the remake personally, but the original has its charm too, you can witness the series in its earliest incarnation, it has the whole text parser and sixteen colors blocky graphics that a lot of people still enjoy, it also has one easter egg that is missing in the remake, and a scene in Space Quest IV may resonate with you differently if you play the original instead of the remake.
The remake has a pretty nice soundtrack, has much more writing in it, has a whole bunch of cameos from other sci-fi movies, TV shows and novels to match the style of the later Space Quest games in the series, and it visually has a retro, pulp, Buck Rogers/Flash Gordon, kind of visual style to match its plot. That being said, some people tend to find the graphics, especially in the final part of the game to be quite headache-y.
In term of puzzles, some of the puzzles have been tweaked a bit:
For those who are allergic to arcade sequences in adventure games, there is an option to skip the sand skimmer sequence (although doing so will reward you no point),
There is an alternate way to deal with the Slot-O-Death sequence,
It is possible to find buckazoids somewhere else on Ulence Flats should you lose your last buckazoid,
The coupons puzzle has been made much less obtuse now that the coupons are included in the game, and not in the game box like in the original,
And last but not least, a cartridge reader has been added in the final part of the game, in case you forgot an important detail written on the cartridge, or in case you missed the cartridge reader earlier in the game.