These are very different restaurants...so it will depend on what you're looking for.
The Storyteller's restaurant is quiet & relaxing & the food we had in 2005 was very good. The decor follows the Grand's rustic & wood feel.
The Blue Bayou is dark & has an ambiance to it. The POTC boats float by while you're dining. The meal can be very, VERY expensive, so be aware of that. The food & service at our meal in March was excellent...but some people have had issues with the service before.
We enjoyed both meals...but definately 2 different experiences.