Well, I don't have CB 10, so I can't compare both versions.
After googling:
- Repertoire database completely revised (I hope for good

)
- On playchess.com the last 40 games of a player can be downloaded as a database (Really?! Great!.. Does anyone care?)
- 'Try out' moves (Does anyone know what it means?

)
- Improved functions 'Opening report' and 'Dossier' (What's the improvement? Can you be more specific, for God's sake? )
- Generation of e-books for Amazon Kindle & Sony e-Reader (Does anyone use these...mhmm..goodies?)
- Training questions work more smoothly (I thought this was no questions-answers game.. But who am I to tell?

)
- Layout of reference database and online database ergonomically adjusted to the screen format (Well, hand on my heart! Very useful. Really! I use it often..)
- Games can be played through directly in the main window without having to open a separate board window (Never tried it!

It can be useful, I suppose..

)
- and much, much more (When I see such a statement I usually think "Yeah, and nothing more.. Was that all?"

)