True, but for the relevant gun (sniper rifle) they all do :) (Destiny)

by Xenos , Shores of Time, Wednesday, January 13, 2016, 15:03 (3477 days ago) @ ZackDark

Obviously they aren't identical, but the only functional difference is that one requires you to hold a button and one requires you press a button. In Halo if I recall correctly your aim was not affected much if at all when hit, you just were forced out of zoom. It seems obvious that the small amount of temporary knock about was supposed to make up for not forcing you out of zoom, but I think the current meta has proven it's not really enough.