TechPowerUp has put together a quick overview of the differences of Intel's current offerings for your reference when purchasing a new machine or considering an upgrade.  The older i7-4770K would run you $310 as compared to $338 for the i7-4790K or $385 for an i7-5820K while the i7-4960X would set you back $1025.  Is it worth upgrading your machine if you have an older Haswell, or going full hog to pick up the $1000 flagship model?  The results are presented in a handy format and while perhaps not an in depth review the results are quite striking, especially the performance while gaming.

"We review the Haswell-E lineup by pitting all its processors against each other and the Ivy Bridge-E Intel Core i7-4960X, Haswell Refresh Intel Core i7-4970K, and Haswell Intel Core i7-4770K. If you are looking to build a high-end gaming PC, or are looking to upgrade, then look no further: This review will tell you which CPU you will want to get to cover your needs."

Here are some more Processor articles from around the web:

Processors