Well, Aftermath is the more approachable one of the two, comes first chronologically, and is not an (insanely) buggy piece of crap :p
That being said, they both pale in comparison to UFO: ET (and the original XCOMs :p), but are pretty fun anyway.

I've been waiting for a deal like this. Bought both games along with Aquanox.

I like Aftershock more, it's better overall to me but the physics of ragdolls can lock up single-core CPU's for like 5 seconds if a guy falls. Otherwise both are great games, already own them here and on disc. The GOG version lacks Starforce!

Both. You won't loose many money.
Aftershock is less buggy now with the brand new last 1.3 patch.
The UFO:Afters are another style, they are NOT X-COM games. I prefer the After ones.

Never played any ufo or x-com game but it looks interesting enough. Bought.

I realize that GOG wants their games sold, and there probably are some players who think that Aftershock/Aftermath are better than the classic X-Com games.
Most of the fans, though, were horribly disappointed by those games. They don't even barely live up to the level of complexity, atmosphere and sheer fun of Apocalypse, TftD or Enemy Unknown.
Claiming that those games managed to improve upon their ancestor is just wrong. They may have shiny graphics, but that's about it.

Deiwos: I missed X-Coms that time and when i try to play it now, it quite sucks (well, i played JA that time and it's my turnbased love), so UFO: AfterWhatever was good for me - kinda. Aftermatch was hardcore stereotype, Aftershock - one or two points better. And afterlight is too new for my comp, so i haven't played that yet. And I am really sorry for that. I believe that Light is best of this UFO.
So.... It could please a lot of people. Some oldschool fanatics hate it, but who ..... cares, right? :)

They're not bad games, but they're certainly not improvements of the original. Anyway, I bought the first in the series to give it another chance. Played it on release years ago but didn't get very far before other (better) games claimed my attention.

Aftermath is so-so (style is great, gameplay is mediocre), but Aftershock is where the series really shine.

I prefer UFO:ET overall, since it has a better strategic and no panzerkleins. That being said, I fully agree that S2 has the best tactical of any of the competitors (JA2, XCOM, the two branches of UFO, etc).
Didn't really like Sentinels though. Much preferred the core game.

Heh, it's funny. Turned on GoG to check if there's UFO: Aftershock in here (cause old StarForce used with original DVD release isn't compatible with Vista, and I refuse to install some crappy drivers), and what we have here? A promo!
Too bad I have, like, 12 hours left and no cash on PayPal ;( xD

Why does the promo page say "from 2.99$" and "from 4.99$" on their page? I thought that was the sale price for each game, not the amount being discounted.

Good offer, although I already have both games on DVD... Aftermath didn't catch me very much, but Aftershock is way better. Yes, it is NOT like original Enemy Territory, but it is very close. Kind of a game that can convince some "modern players" to try old school classics.

Silent Storm was a lot of fun...really enjoyed that one. Would definitely be a must buy.