Having had TackIR 1, 2 or 3, (I'm not really sure which as I bought it 2 years ago), and not wanting to shell out another £100 for something which everyone else said was marvellous but I couldn't get on with, I found a TrackIR 4 with Vector enhancement on Ebay! I was the only bidder and it duly arrived from Malta last week. Today was my first chance to try it. I flew the Tiger and the difference it makes is tremendous. My old one never quite cut the mustard for me, but no doubt someone else would find it great. This one is very stable and there's definitely another fan here. Peter