Novotnus: You mean entire Zork series (just completed mine during this promo) or Zork Anthology?
If you want entire anthology and you like to see the evolution of gaming in this series, go and grab it, it's one of the best examples of how games changed over the years.
If you want a big part of what made adventure games what they are today and enjoy some crazy (and sometimes toilet) humour - grab Space Quest.
I'd get Space Quest first for nostalgia reason and to know how it ended (played only 1, 2 and 5 back in the old days).
Zork is something I heared about but never played before GOG. Haven't played them all yet, so I can't give you a fair review.
Every Zork on sale right now. In comparison, both bundles of Space Quest's is only $2 less than the sale price of all 4 Zork games until the end of the day
I technically get more games with Zork, but either way I get at least 6 games
The Zork's look a little more unique compared to the Space Quest's, but I also don't have any sci fi adventure games as of yet
Tempted to get both just to settle my back and forth mentality