I don't think I'd classify it as a miracle product but it definitely is an excellent product that is worth every penny.
The thing about the Bio is that it is not meant for feather pluckers. Whats its intended purpose is is to promote healthy feather growth. It is not going to stop plucking that is behavior or habit related BUT if it is caused by a deficiency in any of the vital minerals, amino acids or vitamins, it will help correct it.
I personally feel that it is worth a try for anyone that has a plucker.
To keep your bird from plucking the new growth, the other recommendations made in this thread are invaluable.
Here's a copy of the
Product sheet for any that are interested.