Summary: Got exactly what I ordered in a decent timeframe. Bought it to go in a gigabyte ga-z97n gaming 5 mini-itx motherboard along with the Cooler Master Elite 120 Advanced! Great build with overclocking possibilities!(The only thing I would have changed, would have been to order an Elite 130 instead, just for the ease of water-cooling!
Summary: i paid the extra 20.00 bucks assuming i could squeeze out the extra performance. while overclocking on my asus z87 motherboard using a thermaltake nic c4 cpu cooler. i found that I COULD NOT get the cores over 4.2. i was content with this speed. the cores must have a bad clock. i have moved voltage to the appropriate leves. never exceeded 2.25v while testing. even though i was able to boot windows at this multiplier, it would crash when stress testing.
Summary: The 4670k is the most powerful i5 as of the time of writing. It is more than enough for gaming,and suitable for most other tasks also. A professional might consider the 4770k instead for its hyperthreading capabilities. The only thing is that the haswell has poor thermals. Not very good for overclocking and enthusiasts. There is very little reason, if any, to upgrade from a 3570k if you have one.