I was surprised to find that Netflix uses FreeBSD. I was not surprised that Netflix is using freeBSD as FreeBSD is the core operating system used in the secure computing's switches. I have also deployed a number of applications using FreeBSD. I found it to be responsive and very capable. The only thing that I did not like about it was that in order to get full coverage of the applications that you need for a normal installation you needed to include the llonux compatibility later.
FreeBSD represents the little engine that could when it comes to free operating systems.