The problem with all these pedals is that they're well-built and will last, if not forever, than at least a very long time.
The A530's looks like a step up from the A520's. Trying to rest slick Sidi soles on the non-cleat side of the A520's is dicey. It's not a confident feeling at all.
But the A520's are holding up well, so I'll have no good reason to upgrade.
Not that that's ever stopped me.