I have the IPV3, and I have to say, ... i Love my IPV2.
Yeah, you read that right. I love my IPV TWO. IPV 3, not so much.
Oh, The IPV3 is nice, but it's bigger, the fire button sucks ( its like pressing a ball bearing) and it has 1&1/2 useless features, and 1 pain in the ...., annoyance...