Here I have tabulated overclocked performance from Overclockers Club. We see here that the much hotter 22nm i7 3770k @ 4.7 ghz is in a dead even tie with intel's older and much cooler 32nm 2600k @ 4.9 Ghz.
IPC looks like an average of ~5-7% better with ivy bridge. This isn't very impressive at all in my opinion, and I am absolutely confident AMD's next generation Vishera processor will be a larger jump from current FX processors, than this Tick-'Minus' bump from intel.
Not only do these chips generally overclock less, and run hotter than current sandy bridge offerings, The performance does not justify an upgrade from current Z68/2600k/2700k systems.
If you were thinking about upgrading from your current 2600k/2700k, and overclocking to the max, this chip is simply a big fat side-grade.