This ! Ivybridge is the one you want to jump to as quick as you can if you are on 775,1133,115
6 or ANY AMD, if you already have Sandybridge stick with it as you WILL NOT see any real performance improvements! your better off upgrading to either Sandybridge-E or waiting for the next TICK .... Haswell
Ivybridge does support upto 2133Mhz RAM (and hold it there unlikey Sandybridge) so anyone buying Ivybridge and running stock should buy some nice fast stuff (e.g 1866Mhz) and you will see a nice perforance improvement over stock Sandybridge users.
Ivybridge isn't a fail people just a smaller version of Sandybridge so they could use more space for the iGPU and give it a huge boost. Ivybridge was designed with Intel Ultrabooks in mind remember which will not be running stand alone graphics cards so Intel needed to improve in this area.
Overclocking on Ivybridge can be done and I think for the Intel Core i7 3770k
a nice stable one would be around the 4.6Ghz mark with a decent cooler which is not to say considering this is new tech for Intel is really that bad, 22nm will always run hotter with bigger volts then 32nm that's a simple fact because thinner wall's in the processor = more heat saturation.
Hope this help's

lets just hope Ivybrigde prices aren't sky high like around the £300 mark for the Intel Core i7 3770K.
And for the people asking what the performance different is between their Intel 1133/1156 chip and Ivybridge any Intel Core i5/i7 Ivy or Sandy knocks the pants off them part from the bigger 980x the only chip that will give you more real world performance then this is the 2011 3930k or the 3960X