Worlds apart, superset provides powerful visualisation capabilities, but is very difficult to use/setup/maintain (although they just launched as a company [0], so perhaps that will change).
Metabase is a very easy to use data exploration, data vis and reporting tool designed to give insights into data in an easy/self service way for mostly non-technical users.
I've POC'd both, and would recommend Metabase or redash unless you really know what you need out of superset
Pretty similar feature wise and intended use, I did a direct comparison and went for Metabase because it allows you to schedule reports delivered to email/slack (only allows you to schedule individual queries, not entire dashboards).
I didn't demo redash so can't comment on the actual use comparison.
Metabase is a very easy to use data exploration, data vis and reporting tool designed to give insights into data in an easy/self service way for mostly non-technical users.
I've POC'd both, and would recommend Metabase or redash unless you really know what you need out of superset
[0] https://preset.io/blog/2019-10-09-series-a-announcement/