Any guidelines about Red Hat Enterprise Linux STABLE version for Selenium and Appium?

Hi All ,
I am looking for stable version of Red Hat Enterprise Linux version to set up as Sever machine for Test automation using Selenium & Appium.
So any one of you did the same can you guide me on it .

  1. what the RHEL version you used ?
  2. Any specific challenges you faced while running the scripts using grid on client machines
    (Mac and Windows) so did you faced any big challenges in it and still stuck in it ?
  3. SVN with Red Hat Enterprise Linux version ?
    Will really appreciate you feed