The overall opinion seems to be that the 22nm Ivy Bridge represents a relatively small boost to CPU performance (typically 5-20% compared to the 32nmSandy Bridge, depending on the task), a pretty significant boost to integrated graphics performance (typically 40-65% compared to Sandy Bridge), and reduced power consumption under load (around 15-20% compared to Sandy Bridge). Since Ivy Bridge is only a Tick+ release, this is pretty much what we expected. The Ivy Bridge also seems to have a little less overclocking headroom compared to Sandy Bridge, which is mainly important to desktop hardware enthusiasts. The first wave of Ivy Bridge processors are the high end quad-core (plus hyper threading) Core i7 parts, with the more mainstream Core i5 and Core i3 parts due out in June.
If you already have a decent Sandy Bridge system, it is harder to make the case for an upgrade to an Ivy Bridge system. If you have something older, like a 45nm Core i7, or really anything else that is older than a Sandy Bridge, then an Ivy Bridge system will be a very nice upgrade. The Ivy Bridge processors actually cost slightly less than the equivalent Sandy Bridge processors. Ivy Bridge is pin compatible with Sandy Bridge, so many older Sandy Bridge motherboards will work with Ivy Bridge, after a BIOS update. You can also use a Sandy Bridge in a new 7-series chipset motherboard, although I am not sure why you would want to.
Here are some links to some of the reviews that were published today:
AnandTech: The Intel Ivy Bridge (Core i7 3770K) Review
Tom’s Hardware: Intel Core i7-3770K Review: A Small Step Up For Ivy Bridge
Overclocker’s Club: Intel Third Generation Core i7 3770K Review
The Guru of 3D: Core i7 3770K and 3750 review with Z77