I don't have any decent figures on NFR's market penetration, but I do know that the Sourcefire/Checkpoint deal was nixed because of security concerns. While the deal was canned shortly after the whole Dubai ports debacle, it was likely not due to xenophobia. The specter of a foreign government having ownership of a network monitoring technology with wide penetration in the defense sector was clearly unacceptable. I guess the implicit message here is that not many people use NFR anymore.