I would say I'm going to buy this.... However, I'm waiting for an eventual definitive boxed set once all the Paranormal Activity's have been released.
Though they may not release one as well... In which case I will end up getting this either individually or with the other 3 flicks in a collectors pack or something (since the first 3 flicks are already in one).
Regardless, this movie is the 2nd best flick in the series IMO, second only to the original.