I have been looking at this for several months and the conclusion I come to is NO.
You are looking at $800 plus for something like a 15% "improvement" that simply will not translate in to better performance you notice in most situations especially games.
Prices are high and although prices for older cpus are holding up a bit, you are still looking at a lot of wasted $ for almost no real world benefit for most people.
There is probably something else you want to upgrade in your system first that will give a better performance boost (screen, SSD, graphics card etc)