Hehe. I never watched it but I heard it was bad. o _ o
Yes, yes, now I'll have to go through the angry mob of people who just said it was good. xP Anyways, this is only my opinion, but I'm sure that this was NOT Julia Robert's best film. It did not gain much popularity and it didn't really have an "it" factor. =/
What I mean by "it" factor is something like the movie
Pirates of the Carribean. THIS movie had an it factor. It had a few different plots in the story and the story had progressed in a nice pace. Plus, great actors were chosen for this. ie. Orlando Bloom/Johnny Depp. The people who created this movie also took into mind that Orlando Bloom was popular and put him in the movie which made Pirates of the Carribean be more popular. On the other hand.. Mona Lisa Smile just chose Julia Roberts.. Even though she is a really talented actress and is really famous, she wasn't really being talked about during the time it came out.
Again, this is only my ideas..