Paranormal Activity 2 is the prequal to the first, where we see what happened before we saw Katie and Micah be antagonized and understand why everything happened to them in the first place. Old seances and deals don't go unremembered. This entity is patient.
We also get to see what happens after the end of the first film!
Fans of the first are sure to enjoy Paranormal Activity 2. Both films are quite similar, though there are different characters in focus and plenty of new scares are in store. This in itself, makes Paranormal Activity 2 better than the first. Personally, it made me jump about twice as much as the first.
The actors are especially good for such a b-movie. Even if it was a high-budget film, I'd still be able to say I had little to no problems with the acting, dialogue, or general characters. People weren't as clueless as the couple in the first movie; they actually had an idea of what they were dealing with. I suppose that could make it less creepy and exciting, but fans of paranormal shows and metaphysics probably already knew what sort of entity it was from the beginning. This was my case, and that it why it didn't make much of a difference for me on the scary scale.
The only thing you'll leave with after seeing this one is that it entertained you for an hour and a half. Maybe you'll rent it afterwards or buy it, but if this film didn't make me jump as much as I did, you probably would have found it quite pointless. Scary stuff happens when you aren't really expecting it, and it's all pretty random, so it think it'll please most people.
Entertainment is all it has in store. Nothing particularly favorable, but perhaps a little bit memorable. It wasn't bad.