Security: Is it the case? (legitimate question) Usability: It works really well for me, even on old computers. Could be better, but in comparison with the other browsers, it does well. Performance: This I don't get, it's snappy, and light for me, feels more solid and less resource hungry than chrome based browsers

Defaults settings are far from being great, but there's no competition in term of privacy, firefox + ublock origin is still the best option.

And don't forget support for the latest Web APIs. Fewer and fewer new, heavy web-apps work on it. I love everything else about Firefox but if they can't keep up on the API side it's going to increasingly impede my workflow.

This is not 100% fair.

A lot of web APIs are rolled out by Google without sufficient standardization or agreement from the other organizations that ship engines. So Google is being a poor citizen here, but because of their dominance, everybody else is blamed.

I really would like you to explain all of those, especially the first and the last. In what way is it less secure or private than the alternatives?