We'll try and get some 45mm comparisons done, as well as some more expansive tests, but for now here are some results from the Mamiya AF, Phase One D, and Schneider LS 80mm f/2.8 Lenses. As you can see, the wide open performance gets better in terms of both sharpness and chromatic aberration from Mamiya to Phase to Schneider. At f/11, the results are much closer, but this is generally the case with many similar lenses. Interestingly, the Schneider 80mm seemed just a hair brighter at the same apertures.
http://www.captureintegration.com/tests/lens/Steve Hendrix