I thought originally, it's not really X58 or X60 but more H3YZ as the X would be 3 regardless and Y could be either 4 or 5 with the 4 going to regular users and the 5 going to people who they decide to test because the 5 had the newer video player and basically 4 is the stable and 5 is the test but now, Y is 5 for the stable version and 6 is the test version. I doubt they are identical as we would not know without comparing the MD5 of both versions and without
Josh.M or someone else with official information from DISH, no one will know what the real changes are. They should really have people who want to be testers sign up instead of just pushing it randomly as I am sure some people with the test versions do not want to be running test versions and they also probably don't have support because test versions should only be used by those who have technical skills and can accept the problems.