Oh, I see, the -4770K is on sale on Amazon for $309.99 currently. That muddies the waters a bit, but I think I'd still go for the -4790K. Even if it doesn't overclock further than the -4770K (and it may), it would do so with less heat. And at 4 GHz, its a sizable performance increase at stock.
Thinking out loud: I wonder why Amazon's list prices are $10 higher than Newegg's.