I'm not biased toward either Lightroom or Capture One I can tell you. I'm on my third Phase One back (P45+) and liked Capture One when it first came out as really it was the best available. Like Michael, I think--that was then and this is now. After working with both C1 4 beta and Lightroom I'm leaning toward Lightroom not only for ease of use, but also for quality control. I simply have more control over my image file in Lightroom. That is not to say C1 won't improve---alter all this is a beta, tho too long in coming. but right now I tend to convert to DNG in C1 4.0 beta, and work in Lightroom (tho I'm still experimenting with comparing RAW file conversions in both applications).
Does anyone know (jeff??) when the next update to Lightroom will be out that will support Phase One P45+ RAW files so I won't have to convert to DNG first?