The other reviews sum it up quite well. I viewed the 3D Blu-Ray 3D version of this film.
Here's what is good:
The special effects are very good indeed. A lot of money has obviously been put into the production. Some sequences are absolutely magical and enchanting, particularly a sequence with dancing "snow nymphs". The film is at times very atmospheric and showed quite some promise.
The film is downright eccentric and this did leave me laughing on occasions. This eccentricity sits well in both the good and bad categories.
What is bad:
The 3D as mentioned elsewhere is not real 3D but 2D converted to 3D and it is not done just badly but appallingly. It was so bad I was tempted to watch the flat version. If someone new to 3D watched this they would think 3D is almost unwatchable. Some shots are flawless but in others people's heads look dented and misshapen, the background is often nearer than the foreground and even surfaces which should be flat (such as newsprint) look irregular. Don't even think of using this to show off your 3D system. It's awful and I for one felt cheated.
The songs are not memorable. (A rare achievement given that they are based on Tchaikovsky melodies!) Often they simply slow down the pace of the film which is a little muddled and odd in any case.
The uncle has such a strong Germanic accent that he is almost unintelligible, especially for small children but there is no subtitle option.
In conclusion I had heard that this film did not do well and I had seen some shots which showed very high production values. I bought it wanting it to be a little gem but sadly on this occasion I have to concur with the other negative reviews, all the sadder because it could have been sooooo good. Even the real pros can get it wrong I guess.
In fairness I have to add that my 10 year old daughter has grown to love this film. "I got used to the weird stuff." she told me. There is more good than bad in this film. As for the rats looking like Nazis and burning toys - which does seem a little Auschwitzy - most of the analogy goes over kids' heads while when they are older they will at least associate Nazis with the bad guys which is no bad thing when you think about it.