I have used, and compared, Tableau, Power BI, and JMP in terms of visualization. Tableau has the most sophisticated (in terms of professional looking) graphics, followed by BI, with JMP somewhat behind. In terms of ease of use, the order is the reverse for me. In particular, I think good visualization requires easy manipulation of the data, and neither visualization program comes close to the ease and power of JMP. Of course, they also don't have nearly the same analytic capabilities as JMP, but even the visualizations seem somewhat clunky, particularly for Tableau. I find the clunkiness is mostly in the need to quickly and easily transform the data, filter, aggregate/disaggregate, etc. Once you know what visualization you want, Tableau does a wonderful job of making an impressive visual and has many capabilities for providing powerful dashboards. BI is not as powerful, but I find it a bit easier to use and it is certainly much cheaper. However, I don't find either particularly intuitive when exploring the data and trying to find a visual that tells a meaningful story.
