I have had my Track IR unit for a couple of years now and have it with the vector expansion..... have been very happy with the unit.. I saw one of the new track IR 4 units at the IFC conference in Birmingham and the guy there said it was an improvement on the 3 version.... would love to know if anyone has made a comparison or upgraded themselves.....

Although I have only the TrackIR4, I understand that the scope field is wider on TIR4 whereas the TrackIR3 with vector is narrower.

Here is a webpage with the comparisons between the different TrackIR hardware versions.http://www.naturalpoint.com/trackir/02-pro...comparison.html