Rosamund was excellent of course and especially so because it was her big, breakthrough performance. However, take out everything out of this movie that made it great (including in a large part the genre of the film) and her character ends up being more of a caricature and less like a real person. That's where Moore beat her fair and square. Alice was a three dimensional, everyday woman whom we all knew at some points in our life.

No Julianne Moore should not have won an Oscar
You can put a dress on a pig but in the end it's still a pig.