I like that it has all of my contacts in one place, so if someone changes their email address or phone number we can update them right away! It's also very easy to use once you get used too how everything works with your system (like adding notes).
The only downside for me at this point would be having more advanced filters/reports available from salesforce data sources than what they have currently built into prodigy - but i'm sure these are coming soon as well!! If there were any downfalls then its probably just because some functions aren't fully developed yet- which isn;t really an issue since most companies donno know exactly where those features will fall when implementing new systems anyway.