The UI looks awesome, it has all you need to get started with your data analysis right away! I'm really happy about how easy they made this process for me as an non-technical person while still providing tons of useful insights into my business performance (and also tracking customer behavior).
There are no downsides so far - everything works just fine :) So many plugins that can be used together or separately depending on what exactly we want out from our dashboards/reports etc., which makes building custom reports super fast once they're designed properly in mind. We use them mostly internally but sometimes make some public ones too. This helps us keep track over time where things go wrong & help improve overall user experience.