Looks quite cool, very similar in functionality to the PhaseOne CaptureOne Pro software - which it is priced at as well. a Minimum spec of a G5 mac impplies its in the same power league also. Being Mac only may harm sales though especially seeing as how the PhaseOne is multi platform.
and im sure it will run really well on one one of the newly announced Quad Core G5 PowerMacs - especially if your spring for the 16GB RAM and 512MB PCI-X Graphics card options.....:-)
http://www.apple.com/aperture/