Me and the kids watched this movie yesterday evening. We all liked it quite a lot. This is a very enjoyable family movie. It is, not surprisingly, a new twist on the old Jack and the Beanstalk story. The basic elements are there, Jack, beans, beanstalks and, of course, giants. A few new elements are thrown in like a Crown to control the giants, a treacherous bastard responsible for the entire mess and a few other things.
The giants are very well done. The CGI is good to very good most of the time. As can be expected, it is the giants that make up this movie. I would say that they are slightly scary (for kids) and rather funny at the same time. Unfortunately the same cannot be said about the human actors. The acting is generally not so good and sometimes downright abysmal. It is rather surprising for such a relatively big production to have such poor TV-show quality acting.
The bottom line is that it is a very enjoyable family movie. If you watch it as an adult I guess you must have a liking for special effects and CGI, which I do, in order to enjoy it.