It maybe already late to write a review on Aperture 3, but WTF! Better late than never!
Aperture 3 is Apple's famed RAW processing and photo management tool. Until recently I was an regular user of Aperture 2.0, only few weeks ago when my system crashed and I had to reinstall my OS, I decided that I should go for Aperture 3.0. Apple boasts 200+ feature addition but I'm not writing a feature-by-feature review. I'm just gonna write about the features that I was using, how it has changed and how good or bad it is.
The first thing that anyone upgrading from A2.0 to A3.0 would notice is the brand new interface with face tags, geo tags and flags in the library pane on the left side, colourful toolbar with MobileMe, Email, Flickr and Facebook icons along with view configuration buttons which are very handy. Facebook icon for me is the most useful icon, for I was fed up of the lousy java uploaders on the browsers for mac osx. Setting up Flickr and Facebook accounts are really easy and just one time process, you just need to feed your login details and you're done.
Faces is an entirely new feature that has been taken from iPhoto. You can tag the face of the people in the photograph, Aperture adaptively learns and recognizes the faces of the people. It's a very useful feature especially in family/portrait/wedding photography if you want to look for a particular person's photograph. You can even store the details like email-ID of the person
Geotagging or Places is another new feature where in you can pin the photographs on a particular location on the Google map. Yet another useful feature for people always on the move, you can find/sort/browse the photos you took in some tongue-twisting place names like Tlacomulco or Zhexidashagu or Tsomoriri, without having to recall the names. This feature also supports GPS, so if your photograph has the embedded GPS info, Aperture can automatically place them on the map.
The import window interface is slightly changed, but feature wise it's pretty much the same with few changes to like Raw+Jpeg pairs, action script where in you can write your own scripts to automate the workflow. I'm not a geek to write my own scripts, that feature is out of bounds for me.
Another useful thing that wasn't in A2.0 is the "Adjustment Preset". One can preview the changes that happen by using a particular adjustment present just by placing the cursor on it, so that it gives a fair idea of how the photograph will look when the preset is actually applied. Presets are available for auto exposures, colour schemes, white balance and b&w filters. You can even make your desired settings and save them as presets. Its definitely a cool feature that saves lot of time.
The crop tool has undergone few useful changes. Primarily it shows the grid lines which makes it easy to decide if you need to rotate the image or not. Secondly as you crop the image, it gives the effective megapixels (MP) to which the cropped image will be reduced to. In A2.0 constrain to crop ratio was a check box on crop tool, but now it has made a part of the drop box options along with crop ratios, I would have preferred the check box way though.
While fixing the sensor spots in full screen zoomed mode (F, Z) the navigation window that appears on the right hand side, is very intelligently designed. It remains as a small icon on the right and when you move the cursor over it, it transforms into a preview window with the attention area enclosed by the square, as shown in the above screenshot.
Dodge-and-Burn operations were extremely painful in A2.0, it first saved the RAW file to a TIFF and then work on it in a separate window. With "Quick Brushes" your life is made a lot easier for dodging, burning, saturating, polarizing or sharpening a part of an image. It eliminates the intermediate TIFF conversion before making these changes.
Full Screen browsing of the images is greatly improved quickly changing projects or albums. Switching between projects is made a lot easier. Also the vanishing HUD feature is extremely useful in full screen editing of the photograph. This is how it works, when using the Inspector in full screen mode and moving a particular slider, just hold down the SHIFT key and the HUD vanishes and gives an unobstructed view of the photograph. Perfect example of Apple ingenuity.
Advanced slideshows could be easily created using the Slideshow creator including your favourite music, choosing from loads of inbuilt themes, controlling the time and the way each photograph is to be displayed in the slideshow. This is very useful for the pro-photographers to display their work to their clients.
One observation I made in A3.0 is the quick deletion of file. On A2.0, deletion took ages to even pop-up the delete confirmation dialogue box. On A3.0 deletion happens in fraction of a second without any annoying confirmation box which is very welcoming.
Apart from this there are a host of other intuitively designed features that are very useful for advanced users especially in Image adjustments section. One can browse all the features here: Aperture 200+ new features.
The only flip side of the software was the load on CPU. Though I can't give any MIPS numbers, I felt all other applications on my MBP were almost zombielike. Aperture 3.0 itself was extremely slow and that was quite annoying, maybe it's time to upgrade my RAM, but Aperture 2.0 didn't make me feel so. It was a lot smoother and lighter than Aperture 3.0.
Overall for the features it provides, I can forgive its resource-hungriness.