Photo Effects SDK is a must have for any iOS developer using photos in their app(s). I would even argue that the filters provided within this SDK rival those offered in the top selling/free photo apps on the App Store.
The SDK utilizes the CoreImage framework, which in turn allows for faster processing/application of the selected filter. The developer(s) of this SDK should be applauded for their hard work. Simple access to each and every filter API is a huge plus as well. While the sample project offered is great for reference, it's really up to the developer to determine how to visually represent the variety of filter APIs offered by this SDK within their app.
Personally for me, the time saved using this SDK immeasurable. I highly recommend Photo Effects SDK and it's worth every penny paid.