Well the switch pro would allow for more accessories down the line, it's a cleaner install (in my opinion) and while I've never put in A pillar switches I'd bet the switch pro is easier to install. You will only have to come through the firewall once since all connections are made under the hood. And whatever switch wires come with your chosen accessory can pretty much be left in the box.
I did an ARB compressor a few weeks ago and all the wiring for the switches is unused. You wire into the power module under the hood and let it do the rest. I got it for that reason alone. Far simpler for someone like me who knows very little about the electrical stuff.
the lights I've ordered are plug n' play so why is this better than say a Rugged Ridge A pillar switch mount?
Do I need an adapter harness to run my arb compressor with this unit? If I recall you need one to use it with an spod.