I'll come right out and say I bought the PS3 for Killzone 2 and I loved the game even with it's heavy settings making it slow to turn your gun.  I love FPS games, multiplayer, and graphics so I had a lot of fun with it and I'm glad it got me to buy the PS3 because not only did I enjoy Killzone 2, but many other great exclusives.

Now with that said I can't say that I have liked the other Killzone games in the series.  They have beautiful graphics but the gameplay is kind of generic and not much substance.  The story is overall meh and forgettable with an average multiplayer.  Not really sure why I didn't like Killzone 3's multiplayer as much as Killzone 2 but I just didn't find it as addicting. 

Anyways  Killzone and Crysis has these similarities as they are both games that showcase hardwares graphics and they sell well for these reasons, but when it comes down to it neither one of these series has great or phenomenal gameplay.  They are good, but not amazing.  Don't twist my words saying that either one of these series are bad because that is not what I am saying.  Let's look at some numbers.

Metacritic

Killzone - 70
Killzone 2 - 91
Killzone 3 - 84
Killzone HD - 59
Killzone Liberation -77

Crysis - 91
Crysis Warhead - 84
Crysis 2 - 84
Crysis 3 - 80

Now as you can see, they both score pretty well on average and both has made one game with a 90+ metacritic. I would go on to compare the sells between the two series as well but unfortunately  we don't have accurate Crysis numbers due to them being popular on the PC.  I expect sells are similar between the series as well though.

So let me ask, do you think Killzone is Sony's version of Crysis?

Id say yes, since their sales patterns are more in line with each other. I dont think anybody should compare KZ to Halo anymore, its too one sided.

Killzone existed before Crysis though. Both are very fun shooters that push graphics.

KZ2 had amazing graphics and multiplayer
Crysis 1 had amazing graphics and the freedom in the island

They kinda lost it with the sequels.

Killzone 1 wasn't really popular.

I agree with the rest though.  I'm not really sure why either developer has only been able to make one excellent game in each series.  They both focus on graphics a lot but it feels like they both forget to pay that much attention to gameplay and story as well. Both are solid though.

i played both. and killzone is way better. sad though, after seeing the crysis 2 trailer i was really pumped and hyped, the game looks awesome and there was so much potential with the multiplayer, then crytek blew it

"The story is overall meh and forgettable"

I disagree absolutely and completely. The Killzone Universe is deep and interesting. It has history and substance behind it. As I've said before, it reminds me a lot of the Dune universe, which is probably one of the most complex and multi-layered alternate realities ever created. There is so much potential with the Helghast and I can't wait until the next chapter.

Crysis, on the other hand, with Crysis 2, became like the SyFy channel's version of Rambo. Aliens are invading and you're the only one who can stop them, blah blah. I'm not even saying that's bad, I liked Crysis 2, it was fun, but it was also mindless and camp. It was an action movie.

However, I think KZ3 was closer to being great. Some parts were brilliant, like assaulting the drilling platforms or the junkyard stages, but then the next segment might be frustrating, or you'd have too much control taken away from your character for too long. Some of the vehicle stages were annoying. An 85 is probably exactly what I would score KZ3 but with the provision that a lot of the game would be 90+ without minor annoyances bringing it down.

Honestly, the comparison between the two is that they're FPS and speculative fiction; beyond that, I get a much different vibe from each.

I don't believe the question you are asking holds any inherent meaning at all.

I've played both franchises and my answer is; no. Killzone games are actually playable, allthough not fantastic by any measure, Crysis games are utter, unfiltered, pure shit but they look pretty. Yay Crytek!