Aperture's printing quality and comparison
I have just being comparing Capture One 6, Lightroom 3, and Aperture on OSX 10.6 and 10.7 and printing with the same colour managed workflow can find very little difference. Interesting that there is a difference however small. If you want alternative print program have a look at the new QTR print program. It can be used to print to any driver so its not just for QTR B&W. I have used it to print colour from my Canon pro9000.
I would be interested in what you think of it. There is a demo version fully functioning so free to try.