So my Logitech K120 began to feel mushy. I checked this thread, I got it in June of 2014. That's not bad, about a year and a half. But I don't wanna have to get a new one every year and a half, even if they are only $12.
I took the plunge and decided to buy the Corsair K70 with the Cherry MX Brown keys. I'm typing on it right now for the first time. Everything about it feels great.
I went ahead and purchased a set of o-ring dampeners too. I know I type really hard (probably from years of using shitty keyboards) most of the time. I installed the dampeners before I even plugged the keyboard in.

I was doing with and without tests as I was installing the dampeners on all the keys. I'm glad I got them. The keys don't feel a whole lot different with them on, and it makes them a lot more quiet. The only difference you actually feel is if you're hammering away, the impact doesn't feel quite as hard. Otherwise, if you're typing softly, you can't really tell they're on there (aside from the bottoming out noise).
I'm not gonna bother reviewing the keyboard here and just repeating what every one has said a million times in reviews on Amazon, NewEgg, etc. But I will say this: The K70 really is well built. It's very solid feeling. I don't regret making the purchase.