If you are looking for a BI Visualization and Analytics tool and have looked at Tibco and MicroStrategy (to name but two), then this is worth putting on the top of your list.
This application is great for displaying BI content on screens but not really best used for the dumb reporting that tools like Crystal do better - however it can do it but it's a hammer to crack a nut.
This application may also redefine how you think of your BI solution. Get the public version and try it out.
Make sure you focus on the data organization. The BI tool will run at the speed of the data....therefore if you have to have joins across multiple data sources of a fair size, these should be connected outside of Tableau in production environments. Alteryx is a great tool for merging data sources and having workflows to support it.
Simple, quick and easy to create simple outputs for the novice; very capable to scale up and get really complex for the expert (Desktop version). Some quirks around how calculations work need research/training.