Good question, Mark. Files from Canon 1ds, 1Ds2, 1Ds3, 5D, 5D2, various Nikon (including D3x), some Olympus, DNG (not raw) from Hasselblad and Leaf backs. A mixture of current and older files as you can see from the cameras. I did not find a single file where I felt C1 gave a better image than LR - and for me that's the only criterion that counts. That LR is faster and easier to use IMHO, with good cataloging, is a bonus. The only time I found LR outperformed was by Phocus on Hasselblad raw files (not DNG), and so obviously I use Phocus for H raws.
Another bonus is LR's printing abilities which are vastly improved with each update.
I have tried all the other RC's except Aperture and found nothing as good as either LR or C1. So as soon as I have time I'll have a poke around A and see how it goes.
I have no allegiance to any company - hardware or software - and as soon as I find something better I change in a flash. These competitive days I need every bit of technical advantage I can get.