Unless you work professionally with video and need a great deal of control over compression, QuickTime Pro should be adequate. If you bring a lot of video onto the web, especially with specific sizes and download rates, the developer edition is for you. Sorenson Video Developer Edition has several features over what's available with QuickTime Pro. Developer edition offers control over encoding speeds, called Quick Compress. This can nearly cut encoding time in half, while only marginally losing quality.
Developer can also automatically detect when a scene changes and insert a key frame.
This improves quality between scene changes. Other features include flexible data rate tracking, which can control varying data playback rates, improved streaming support for Internet streaming, and playback scalability, which can alter playback quality for the particular system. The developer edition also support custom watermarks. Finally, the developer edition has G4 AltiVec support and also support multiprocessor Macs, which would be quite useful with a multiprocessor G4 computer. I tested the basic and developer release of Sorenson Video and also the Cinepak codec.