Surely that's software, not hardware. Hardware is the actual physical camera body, the lenses, the quality of those lenses, the sensor, stuff like that. So Sony's eye AF is better; the Nikons have much better ergonomics, for me. Side by side in a shop, the Nikons felt tougher too.
I looked at (several) Sony ML cameras, as a small, lightweight 'travel' alternative, but each time, was put off by what I felt were poor ergonomics and control layouts. I've no doubt they are brilliant picture taking machines. I bet if you put a load of good pictures up taken on different cameras, nobody would be able to tell them apart (or even care) in terms of IQ. I don't think you can really put a Rizla paper between brands in this respect. So it comes down to other features, such as ergonomics, system compatibility etc. AF performance isn't a big consideration for me, as I don't do sports or 'action' much. But at a recent music gig, in typically challenging light, the eye AF was working better than I'd noticed it before, proving the FW update was of positive benefit. Not being someone familiar with other systems, to me, this was just amazing, and I don't care if another brand's AF is 'better'; it's good enough for me!
Plus there was a lot of stick given over the lack of lenses on launch. There are now 11 FX lenses, within 18 months, which is more than Sony had in that period. Each one seems to get rave reviews, and my own experience of just two of them, proves they are a step up in terms of IQ. So it's all very positive.