The point with most of these technologies is that none of them are really critical. Eyefinity brought something genuinely worthwhile so Nvidia implemented it too. Gsync is clearly going to be very popular, the reviews have been exceptionally positive and AMD has already shown they are early into their own implementation and I fully expect we'll get competition here too.
The other things like ShadowPlay, it may or may not get implemented by both parties, but we can clearly see its not as fundamental. For some people it matters more than others, the people who record and stream, a minority, will care a great deal about this one but most probably wont ever care.
There are also lots of smaller differences in the drivers features that haven't been mentioned, like triple buffering, like openGL extensions, like draw ahead queue, profiles, power management etc etc. But by and large these are all below a threshold of importance for those who have commented. The differences are actually really large, but most of the time all you do is play a game, and the GPU marker when you are doing that by and large doesn't matter much. You aren't going to enjoy a game a lot more because of a special layout of antialiasing, but it might change how you perceive the quality of the graphics a little bit.
I think this is vastness of difference but also the small impact (most people play with the defaults most of the time, I assume anyway) is why most decisions are based on price/performance and features usually get boiled down into an argument of quality of the driver. Its not really accurate to do that but its the overall impression that comes out of all these small and sometimes subtle differences. I think it would be really nice to have a really big roundup review of these differences, looking at the impact they have on IQ and such so that it was more obvious what those differences were, because unless you have owned both cards in a generation you won't realise just how many differences there really are.