VUK is a neat game, and if you're familiar with the SA engine it will make sense.
I had a little trouble with understanding the list building/equipping mechanics (but I had that problem with SA1 as well), but it's nothing a friendly group shouldn't be able to work out together.
All that said, SA2 has pretty much everything in it that both SA1 and VUK had (plus lots more bad guy options; seriously the lurker section is half the book) and since you'll be playing as the bad guys every other game anyway, I'd suggest just going for the main game (which cleared up the sometimes confusing list building mechanics nicely).