1) Intel Xeon E5-2695 v3 ES QEY6 2.2GHz (160 dollars)
This late stage of E5 v3 ES game, it is just not worth it.
Looking at the ebay seller post of CPUZ , QEY6 is a earlier ES chip, 14 cores turbo to 2.5 ghz.
You may have compatibility in the future.
With your budget of $250
Instead, I would look at E5-2678 v3 . E5-2580 v3 or E5-2683 v3 QS or Retail version.
Last week, I picked up a pair of E5-2680 v3 , tested them on Asrock X99 with All-Core-Turbo mod.
12 cores @ 3.3ghz.
With retail version of the chip, you would be sure it would be support for many more years.
Regarding of v4, unless you have a specific need , I like to stay with v3 QS or Retail chip.
PS. To give you some idea, I paid $155 each for the E5-2680 v3