I've used FreeBSD for over twenty years. I started with it somewhere around release 2.2.x. It's come a long way. It's an amazing product.

Take a gander at the list of products based on it (wikipedia). I don't believe that list is exhaustive by any means. The operating system is at the core of things many of us touch every day.

Some notes

Other Information

Of potential interest is Wikipedia's comparison of BSD operating systems and the BSD family tree.