I've had a Track IR4 for a while now, works really well with COD. It is nearly as good as the 5 and can be picked up quite a lot cheaper and you can use the track ir 5 software with it which is superior to the 4. Its also very good for ARMA2 and Rise of Flight which I imagine a lot of you simmerd also own.
Ebay is aways an option if you are struggling to justify the cost, although they do sometimes sell second hand at nearly new prices! just goes to show how in demand they are.
Buy one, you will never look back! (in fact thats not true at all, you will 'look back' when ever you like, just by turning your head slightly
)