Thank you for commenting. One of the main differences is that I think 321 Analytics provides more functionalities "out-of-the-box". You don't have to install plugins, buy add-ons or something like that. E.g. just the heatmap feature costs 199$/year for matomo. With 321 Analytics you get the whole range of functionalities (as well as future updates) as one package without hidden costs or the need to extend the app with add-ons or plugins. Furthermore I like to think that 321 Analytics is also a bit nicer in terms of UI. Another advantage of 321 Analytics is the way the data is structured and how you can therefore filter that data. You can pretty much create infinite numbers of filter combinations to get the exact insights that you want.

321 Analytics is not free. But I think a price of 50$ for the current product is not too expensive. The annual renewal is just for further updates/support after the first year - it's impossible to sustain development otherwise. But you do not have to renew the license - you can terminate the renewal at any time.