Recommendations to others considering Flow:
Use it. It's seriously great.
It's worth thinking about where it will fit in with your existing tools, however. Flow supports file uploads and often it's very helpful to have files associated with comments/tasks. But, if you choose to do this, make sure it's agreed upon amongst the team. Without that policy in place, you'll have some files in Flow, some in Dropbox, some in Drive, etc. Review collected by and hosted on G2.com.
What problems is Flow solving and how is that benefiting you?
Flow makes it easy to delegate tasks to anyone and track their progress over time. For example, I can assign a task to Tom (UX Designer). He can chime in and then delegate the task to Sarah (Visual Designer). She can chime in and delegate it to Caitlin (Information Architect). All of this happens in the same thread and all comments/files/date changes/etc. are very easy to follow.
Flow is the best tool I've found to see who's working on what, when it will be done and what's happening with it at any given moment. Review collected by and hosted on G2.com.