Red Faction or Prototype?!

I'm looking to get one of these new releases soon, but I have no idea which one. I watched a Quick Look of Prototype and it looks pretty damn sweet, but I've played through the demo of Red Faction multiple times now and it plays really well. I'd like the opinion of someone who has played one of the games, or better yet both of them.

There is another topic already asking this same question where you will likely find some informative responses to help you out.

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