The representation of Beethoven himself is as good as it gets. Gary Oldman is superb as always. Other notable performances end with Isabella Rossellini.
As for the story itself, it's pure fiction fabricated on the premise of existence of a mysterious letter to a "immortal beloved". Those looking for an accurate biographical movie will be left with disappointment. As for how good the fiction is, well, it's not great...
In conclusion, I gave it 7 stars for portrayal of Beethoven as he might have been.