Per,
For some reason I thought you were already shooting MFDB. But anyway I have not used the 54s but have used the Leaf 65. I have shot both tethered and to a card. Some quick notes...
Post processing is not much different than Canon files, except I thought they looked a lot better to begin with, especially in skin tones. At the time I was processing in Aperture and outputting into PhotoShop of course.
My own problem shooting tethered was pilot error, me not being familiar with the software. That was in a studio on a G4 Powerbook, AC power. Shooting to the card was flawless.
Higher iso's were not great, 100 is good, 200 is good but not as good.
Capture speed was fine with me, about the same as your studio strobes anyway.
For the next few days I am shooting with a Phase P45+ for my next comparison. I will say that those files put my main computer to the test. 223 mb tiffs in CS3 are taxing on my dual 2.7 G5 with 8 gigs RAM.
Anyway I know we talk to the same people at MAC and Leaf but I could also refer you to my pro rep at the dealer I use who might be able to help you out. Send me an e-mail to
SecondFocus@mac.com if you want the info etc.