The differences are so minor, it really doesn't matter. Some will say go Ivy Bridge-e, for better sli/crossfire performance (minor difference, it is not huge). Basically an ivy bridge-e 6 core cpu is obviously a bit better than a quad core 4770k. But the differences are pretty minor in gaming. So in the end...... it doesn't really matter, it will boil down to deals and money. IF you got the cash for a 6 core, might as well go for it. Or if you want to save a bit on the cpu, and get better a better gpu (s); then go for the quad core.
The haswell is a bit more mature to atm (since it has been out longer). Runs solid.