(People born in the 80s will appreciate the "TrackIR 5 is alive" marketing campaign.)
Now, I'm not about to go out and buy the 5, nor am I advocating anyone do that. But what's really cool is that the TrackIR 4 is now less than $100. You should all go out and buy a TrackIR 4! Stimulate the economy! Have waaaay more fun flying!
That's my $.02.