The only thing that I am aware of that it does not support is IP translation. Like every other piece of security technology on this market it has its strengths and weaknesses.
Lets see everyone's response to that.
Design you solution around each products features, then balance your budget accordingly. Why buy a huge UNIX box, when a Intel could do. The market is responding. Security is not something you can buy, it's something you do. The only thing that I am aware of that it does not support is IP translation.