Like Makosuke I've been using Delicious Library since Version 1.0. In all that time my biggest complaint has been the introduction of the horizontal details pain <- notice intended pun ;-)

I have hundreds of movies and albums and well over a thousand books cataloged so far and the application launches quickly and has been very stable.

On top of this I can now sync with my iPhone. Two thumbs up!

I dropped one star in "Support / Documentation" due to the lack of online help but you really don't need it as the application is pretty intuitive.