Blender is what I point to when people tell me open source is doomed for failure. There isn't anything that comes remotely close in terms of features and ubiquitous support, and its free. Honestly the best example of open source done right.
good-software-takes-ten-years-get-used-to-it
Linux, Firefox, Chrome disproved "open source failures" twenty (and over) years ago. Nice to have another app in the mix.