Haven't read the book so I have nothing to compare this movie to. But I don't think I would regret not having read the book first. Well the movie is good enough that I don't think I shall be reading the book anymore, I will rather watch the movie again. Having been in the fashion industry I can relate to this very well. "The Devil Wears Prada" is director David Frankel's first theatrical feature film, however, it's by no means his first important job, as Frankel perfected his craft directing several episodes of the famous TV series, "Sex and the City" (also inspired by a "chick lit" source). In many ways, "The Devil Wears Prada" retains the feeling of Frankel's previous work and it's probably the obvious next step in his career. While it may not be the most original film ever, it has quite good features, such as a very good edition (by Mark Livolsi) and a well-selected soundtrack.
Many words have been written about Meryl Streep's excellent performance, so I'll just say that she was perfect for the role; as she gives a deeper, more complex personality to a character that essentially exist to be mean. While Streep's performance is essentially what makes the film to stand out from other similar movies, credit must also go to Anne Hathaway and Emily Blunt, who play Miranda's two main assistants. Hathaway as our main character, Andy, delivers a quiet, subtle performance that allows her character to be likable, especially as her actions begin to show the slow but constant effect that Miranda has in her. Emily Blunt is the film's best surprise, showing a great future and a big talent for comedy. Finally, Stanley Tucci has a minor role, but shows off his scene-stealing abilities and makes gold of every moment he appears on screen. The rest of the cast is quite effective, but nothing really as special as the four main characters.
Personally, I think that the film's worst problem is the many similarities it shares with other films, as it gives the feeling that the story lacks originality. However, "The Devil Wears Prada" makes up for this flaw with its light-hearted tone and its big charm, as it's a film that doesn't take itself too seriously (as other similar films do). Also, Frankel's past directing a TV series becomes too notorious at times, making the film look like an extended chapter of a TV series; however, this is not really as annoying as it sounds, and it's probably due to the act that this is Frankel's first feature film.
"The Devil Wears Prada" is quite a good film for a nice evening; it's charming, funny, and most importantly: entertaining. It's always a joy to watch a very talented actress at work, but it's also a joy to discover three new talents (Hathaway, Blunt and director David Frankel) having a chance and making a good job. It may not be a life-changing experience, but this devil is a nice surprise.