I am now trying to use Aperture on my new Macbook to organize my photos. After a few weeks' usage, I really like the program's simple interface; powerful editing / organization functions; and many many plug-ins are available. I can upload photos (together with notes and captions) to a number of social sites including Picasa, facebook, blog, gmail etc all in Aperture. So just one program can solve most of my photo organizing / uploading need. Cool.
However, I have a few complain about Aperture:
1) It's doesn't work very well with the Pentax EXIF - it can't read the lense's model name. Adobe's Lightroom, on the contrary, can read the full name of Pentax lense without problem.
2) The RAW interface of Aperture doesn't not have a quick preset of cloudy, sun... etc to choose. It just have the color-temp. slider to work on.
Overall, I rate the program at 85/100.