My own A99-D600 ISO test

enough so that the test needs compensation.  Almost looks like a 1/2 stop difference to me, the Nikon being that much lighter.  So, that highlight is blowing out on the Nikon, but the A99 looks noisier.

If I mentally compensate for the differences....then I'm not seeing such a huge real-world difference.  Bit of a noise edge to the Nikon, but not enough to influence a purchasing decision, imo.  It looks to me like you'd have to dial in both cameras, really, to get the best exposures.  Also, in this case you've got a lot of range between that highlight on the orange and any of the shadows.  Not sure what device could really handle that in a single shot.  The scene looks like a candidate for stacking to really get the whole shot.

So, I'd be defaulting to the other specs to distinguish between them.

--
tex_andrews
"Photography is the product of complete alienation" Marcel Proust
"I would like to see photography make people despise painting until something else will make photography unbearable." Marcel Duchamp