The verdict
For a small B2B team that mainly needs a handful of marketing and sales dashboards, I'd pick Databox. It is the lighter route, with templates, alerts and client sharing, and you do not need an analyst to keep it going.
If your data is messy, the questions keep changing and a team of analysts will own the model, pick Tableau. It is strong at exploration and governed reporting, and the free desktop edition is a fair way to learn it.
If nobody has time to maintain a data model, Tableau will get in the way. If you need deep historical analysis, Databox is limited. Count users by role before you price Tableau, because the mix of Creator, Explorer and Viewer licences changes the total a lot.