The A530 is like a normal mountain bike SPD pedal, except with a nice platform on the other side of the SPD mechanism. It doesn't, nor does it purport to offer any extra support to a clipped-in shoe like the A520.

What the A530 does offer is that you can pedal as well on a pair of SPD shoes as any ol' shoe because the platform side is large, supportive and non-slip. I have a pair on my commuter that I only wear SPDs for if I'm going for a long (>30 mile) ride; otherwise, I'll mosey along comfortably in normal shoes. The A520 doesn't work well with non-SPD shoes because the presence of the SPD mechanism does not allow your non-SPD shoes to grip adequately on the pedal.

I don't really have any problems with any hot-spots or support issue with my A530 with Sidi Dominators, but I also don't have any such issue with my dual-sided, no-extra-support mountain bike SPD pedal (PD-M959). YMMV.