To start with, any movie in which Helena Bonham Carter gets naked is a good thing.
This is a weird weird movie, but good pacing and casting saves it. A more disciplined director could have turned it into a cult classic.
Steve Martin is convincing in a challenging part. He is a fine actor.He brings just enough comedy so the movie doesn't descend into the land that light forgot. This edge gives the film strange believability.
Laura Dern is also exquisite walking a fine line to achieve a balance between farce and drama. Her character, blondness and 'hard body' look contrasted effectively with HBC's petite, auburn wickedness.
At the end, I wanted to watch it again to appreciate the fine points I missed the first time through.
I would describe it as a darker " The Whole Nine Yards".