I really like this application. The tools are flexible and allow you to customize the blur effects in a lot of different ways. The vividness slider also does some things that are different than other apps and can be fun to play around with. I use Focus as sort of a last pass editor after running photos through other image editors.
One thing though...the application refuses to maintain window size as you open new images and it really drives me nuts. Other apps from Macphun dont have this problem so its strange.
theNakedApe about Focus 2