What I found is I don't think it's the AC, it's their control system. When I drive out of my garage and it's cool in there, it will blow ice cold regardless of outside temp.
BUT, if I leave the car outside, and it bakes in the sun, then it never wants to cool. It seems that the temp sensor is mounted in the dash (behind the grates below the controls). I'm thinking its getting cooled from the vents inside the dash, so it reports a cooler temp than the car really is, hence the AC sucking.
On my GM truck, the sensor is mounted in the roof liner, above the driver. And a little fan sucks air in there. The AC on that is awesome.
I was thinking off pulling the unit out of the dash, and installing a little fan behind the grate to suck the ambient air in there.