We moved from Tableau to Looker and it blows me away how much you have to spend to get good performance and a good dev experience.
My (somewhat shallow) impressions of tableau is that it was built as an excel 2.0. Including all the bells and whistles. But it was not really tailored to our use-case of visualizing SQL data (without all the bells and whistles).
We had some requirements that does not seem to be supported in superset though. The filters implementation is horrible as mentioned, and the killer feature is to be able to group by a {{variable in a dropdown}}.