The main new feature is support for more than one iPod or local repository. Each iPod can be loaded or ejected individually and scripts are called before loading (gtkpod.load) and after saving (gtkpod.eject) with the mountpoint as the first argument. This allows you to issue any commands necessary to access the iPod, for example when you need to mount the iPod manually.
Support for coverart has been improved. You may have to select your iPod model from a list of available models if your iPod cannot be identified automatically, as is the case for iTunes mobile phones or the new 6th generation iPod Nanos. Coverart embedded in the music file (APIC tag) can now also read. Support to read the coverart from specified files is still available though. Please note that at present APIC support only works when adding tracks directly to the iPod. It does not work when you add tracks to a LOCAL repository first and use Drag and Drop to move the track to your iPod.
Additional new features are preliminary support of h.264 video format, sync script for notes from Tomboy, enhanced support for volumne normalisation (iTunNORM flag and MP4 replay gain tag are supported) and by-track options for start time, stop time, skip when shuffling and remember playback position.
Many bugs have been fixed as well. Have a look at the changelog