xD leafer, the general consensus was that I can't crash into the guy infront if there's nobody there... :P
On a serious not I did use Track IR for a few months in 2010 and I found it to be fantastic (both on wing and in lead). Unfortunately, mine got damaged in a move and I never replaced it. It's a fantastic piece of kit which I will be getting again this year. I learnt to fly formation without it, spent 4 years flying right wing without it and did just fine. Having Track IR doesn't make you a better or worse pilot, it's just about what you get used to. It's unusual to adapt to at first, but after a while you get used to it and really start to appreciate the benefits. So, is it worth it? Yes. Is it essential? No.