Time will tell. My wife's Verizon Samsung Galaxy S6 just received 5.1.1 today. Too soon to tell what is different, other than that there is supposed to be a patch for the Stagefright virus.
I'm new to the device only have had it since the 17th of August, just was surprised to not be current with all the scares with stagefright etc.. my Galaxy S6 was patched up but ofcourse it was on T-mobile.