Actually, I would. Not because I'm a BSD hater, because we actually use a lot of BSD at $work.
But instead because I reckon I could safely win a bet with you that Netflix do not use the vanilla version of FreeBSD.
Most people I know would agree with me that the secret sauce will forever stay secret.
Sure, without a doubt Netflix contribute stuff back to FreeBSD. But I betcha it's not ALL the stuff. :)
The same goes for other famous FreeBSD users, e.g. Juniper Networks.
I'm happy to recommend FreeBSD to people, but if they're looking for Netflix or Juniper level network performance, they'll need to know they'll have to do the donkey work themselves because there's not a cats chance in hell they'll magically get it "out of the box".