I'm sure I'll give Lightroom 5 a try and see what they have added to it, such as iPhoto import. So, my question to the Lightroom evangelists is "What does Lightroom do that Aperture does not? What is the killer feature that an Aperture user would upheave his exiting libraries and switch for?"
It reportedly has better noise reduction, better RAW converters, and apparently a new healing brush. It also has more users, so plugins, tips, guides, and editing actions are far easier to download and find. Aperture and Lightroom used to be neck and neck for support and plugins but now I feel like Aperture is by the wayside.
I don't think LR is as good for organizing photos as Aperture is though.
To each his/her own...but I am getting a little fed up with minimal Aperture improvements as well. I am not a pro, but I feel like Aperture has been delegated. I am already flirting with LR4, but if Aperture 4 isnt out by the end of the year, I think I am jumping ship.
Also whoever was above was saying that you can do MacPro work on imacs is misinformed. Perphaps they should spout that off in the MacPro forum...I don't think you can get 12 cores in an imac.