I find it hard to properly rate this film. I'm a bit biased because I'm glad the novel is actually being made into film at all, and that they're doing it in 3 films (as the book has 3 parts) instead of trying to condense it all into one.
I can't really compare it to Part 1 because Part 2 has a completely different cast of actors, etc. so continuity is skewed. I enjoyed both Parts 1 and 2, but Part 2 definitely has the bigger budget look (i.e. more CGI). I'm not sure which film I liked better. Many others have debated which is the better cast, director, etc. but I think there is some decent acting in both. However, after seeing the first film, it took me a while to adjust to the new cast. Upon second viewing, I was accepting of them.
Let's face it, it's a tough job to make all the details and depth of the novel fit into a film. People who've read the book will understand the story and characters better --- and will either hate the film by comparison to the book, or (like me) enjoy seeing how the book has now been turned into a film. People who have never read the book will probably not follow the plot well enough, and there's not really a lot of "action", so they may not like it.
As a film, it's had to be simplified a lot, and characters are very one-dimensional (as in most films). It looks more like a very good, high budget made-for-TV movie than a proper film release. There is far too much usage of "Who is John Galt?", as other reviewers have commented. I won't say anything about the story itself, so as not to give anything away.
I've heard mixed reviews on how the film did in theatres, mixed reviews by fans and critics, and that they lost a lot more money on Part 2. Personally, I'm looking forward to Part 3 being made. I'm curious to see how they'll end the film trilogy and how much continuity it will have from Part 2 --- will it be another new cast? Who knows.