Decent watch, probably won't watch again, but can recommend, especially for a younger audience.
Sometimes it is fun to see what they're offering to the kids, and you run into something familiar like R.L. Stine, and you even hop into the way back machine to see some surprises: like Emily Osment (Gabi, "Young and Hungry"), Brittany Curran (Fen, The Magicians), and Tobin Bell (Jigsaw, SAW).
The story itself is solid, if juvenile (it IS designed for a younger audience), and the actor is a little over the top, but I think it is a combination of good writing of silly characters for kids and quality actors.
Not only does the cast do a great job of the teen drama and typical family infighting between siblings, but the real shining moment of the movie is the "Evil Thing". It is amazing what they can do with some simple practical effects and good camera work.
If you're looking for a "scary" movie to sit down with the kids, this is a good choice.