Dino de Laurentiis [Army of Darkness, Dune] takes over as executive producer which guarantees big special effects. And, believe me, this film tries to pull out all the stops. However, I felt like all the big explosions, latex prosthetics and buckets of blood were less effective than the simple scares used in the original. Sometimes less really is more!
Damiano Damiani takes over the director's chair of Stuart Rosenberg [Cool Hand Luke, Brubaker] who did the original film. However, Damiani is not nearly as skillful as Rosenberg in creating a real sense of terror and dread. This one simply lacks the emotional punch of the first.
Part of the reason for this is that the actors who play the Montelli family are miscast. They just don't feel like a cohesive family unit. Many of their performances are just O.K. and no one really gives an outstanding, jaw-dropping, performance. Therefore, it's hard to get upset when they meet their demise. The audience just doesn't get that emotionally invested in them.
The reviews on IMDB are all over the place with Amityville II. Some love it. Others hate it. I've seen hundreds if not thousands of horror films in my lifetime and while Amityville II is not a poorly made film, I just can't get too excited about it. I prefer the original by far.
For more info check out the film's entry in IMDB.