We enjoyed the ability to share a session. This session allowed end-users to share a dashboard, manipulate it, and collaborate on the results in real-time. See more here - http://robertbgoodman.wordpress.com/2013/05/24/real-time-data-collaboration-by-qlikview/
Start slowly. Work directly with the business users to validate the data prior to publishing. The tool may expose some interesting data quality problems that should be addressed in the source system(s).
We chose to implement the solution in-house. If you have a lot of time sensitivity, I would recommend engaging a professional services firm to speed up delivery. Make sure you spend just as much time on structuring your data as you to on the tool!