In all honesty, the only reason I swapped from my mk3 to the a3 was for the eye AF and better low light.
I shoot wide open 1.2 - 2.8 on my MK3 and about 30% of the shots would be out of focus by a smidge (I had all my lenses calibrated to each of my MK3's)
But I seem to be nailing the shots with tack-sharp focus at 1.4 on the A3.
The dynamic range is pretty decent too, I've got a lot of option to pull back shadows, this I couldn't do as well on my MK3.
Also, the EVF is pretty handy, even though I was used to using the meter, I just seem to like it more.
I don't really care for the nitty gritty pixel peeping details etc, but more the functionality of the camera.