For CIRAD and Bioversity, I created a new Drupal 7 module to import biological data from a Chado database using Migrate. It requires the Tripal module, a project which offers an integration between a Chado database and Drupal. This module declares a destination plugin for every Chado table we used for this project, but it can quite easily be extended for most existing tables (see documentation). Thus, it fits in well with the Migrate framework; for other aspects, like exploiting the data source (e.g. JSON), no need to reinvent the wheel, it is enough to implement some natively provided source plugins. Besides, by relying on a proven module such as Migrate, you can take advantage of other aspects such as rollback and incremental migration.