Probably gives more fine grained loss quality to the screen. IE does what VRS is supposed to do better.
Notice that I said "noticably" in my previous post. If both solutions give results that are essentially invisible to the user, then we can call it a wash. But that doesn't mean VRS2 isn't doing things marginally more efficiently.
It's just not something we will notice for a game that is well optimized for VRS in general because it only probably means like a few fps in actual practice.
So a well implemented VRS software solution(call of duty, dead space patched etc) is technically inferior to hardware based VRS 2 but not by enough to actually matter to the end user.
You should watch Martin Fuller presentation on vrs tier 2.