David Biedny has a podcast on Aperture at Attention Photoshoppers
. It's about an hour long, and goes into the strengths and weaknesses in some detail. Aperture runs well on a quad-core mac with 12Gig of RAM, but lesser machines may struggle.
The Attention Photoshoppers episode on aperture is episode 6. I enjoy the podcasts, they are entertaining and informative.