According to Tweaktown, Haswell's heat spreader is lower than Ivy Bridge's (by .04mm) and this *may* require a different mounting kit in order for existing cooling systems to work.  If your cooler is spring-loaded then you should be fine though as the hole spacing remains identical to LGA 1156/1155.  The good news is this should address the horrid thermal properties that Ivy Bridge exhibited, particularly if Intel opts to solder the IHS to the CPU die again, as they do now with other chips like Sandy Bridge E.  

If this chips are good OCer's with good temps, I will be an early adopter... I've already got my money ready! :biggrin: