Tell me something about Rage. Why or why shouldn't I buy it?
It's worth $5. It's not worth any more. I bought it for $5 and felt like I "kind of got my money's worth."
Basically, it's the definition of an average game.
Is it bad? No, not at all. But is it good? No, not at all. It just ... "is." It's a game. It'll keep you entertained for a bit with it's average story, average characters, average graphics, average gameplay, average guns, etc.
Like I said, there's nothing terribly wrong with it. But, honestly, during this sale, Steam will have so many much better games discounted to a similar price. So why get the average game, when you can get a great game.
Unless you're out of things to play, you can do better elsewhere. That said, if you do get it, I doubt you'll feel like it was wasted. And if you're in the mood for a shooter, you could do worse.