i'm hearing they are toasty hot and don't OC as well, and oddly that the E0 stepping (ES) is worse that the E1 stepping (retail). though those are only rumours from the interweb. Tweaktown have a stable 3770K ES OC'd to 4.72 its at 98degC at load. The corresponding 2600K was a lot cooler. The 3570K seems to run cooler than the 3770K.
That said, i'm still getting a 3570K, OC to 4.2-4.4GHz, it'll give me PCI-E3.0 for the 2013 GPU upgrade, and more power than I really need.