I wouldn't neccessarily say it is my favorite film musical to date, but certainly in the top 10 and the best musical in the last 5 years (which there are quite a few of, recently, musical renissance?).
I thought Depp was superb. I mean his voice is untrained, but unlike say Gerard Butler as the Phantom, this was a bonus. He was completely immersive and mezmorizing. Quite honestly, he nailed the character by giving him a rock and roll sound. Bonham Carter was very good as well, albeit her voice was lacking compared to say, Angela Lansbury on the original cast or the woman in the revival I saw in 2005, but she acted the part well enough and was ghostily beautiful and memorable as the macbre and ambiguious Mrs. Lovitz. The rest of the cast was superb, with Rickman, Cohen and the actor playing Toby nailing it. Johanna was actually likeable for a change, but Anthony was as annoying as ever, but at least he was well acted and still has the best song in the musical.
The musical itself is a masterpiece. The complexity of the story, the music being able to tell the story and its manipulation of the audience is all a tribute to Sondheim. While I still think the elimination of The Ballad of Sweeney Todd (just once, would be nice?) and the judge singing creepily Johanna, it was still a masterful adaptation and certainly the best film adaptation of a stage musical in probably the last 30 years (Chicago would be an arguable comparison). The movie flows perfectly and is engrossing and the end just leaves the audience to wallow in their own misery.
Definetly one of Burton's best and a triumph for everyone involved. 9/10.
P.S. I love people calling it Little Shop of Horrors redone, when the musical predates that film and show and the story is MUCH older.