An Aperture User Looks At Adobe Lightroom is an interesting look at Adobe Photoshop Lightroom from the point of view of an Apple Aperture user. I've never used Aperture (it's Mac only) and am quite a dedicated Lightroom user for my photo organizing need. Some of the points noted are fairly "getting used to" based. I'm personally used to some of the UI bitches he has, but everyone will have their own interpretation.
Noted deficiencies are ability to upload to flickr (meh) and lack of dual monitor support (agreed).
Definitely a good look and review though.