Apparently the 4790K has better single-threaded performance than the 5960X due to its higher base clock, but the 5960X has more powerful cores - and 8 of them.
yeah i have read that higher clock speed is better then 6 or 8 cores in some cases and the 4790K can be over clocked to 5 ghz with a badass cooling set up Kreygasm
The 5960X is overclockable too. I'd say around 4.5 - 4.7GHz would be the sweet spot, but it depends on your luck in the Silicon Lottery what your maximum overclocks can be.