We are using Podio for a lot of other things (Marketing, Sales, Recruiting and Project Planning, Development Process, User Research & Testing) that it just made sense to have every thing at the same place.
But I must admit that at the time, we didn’t look for specific alternative for Product Management tools. In the meantime, I have try some of these specific tools (such as Aha! or Product Plan), but it didn’t decide me to switch from Podio to one of these tools.