Most of our clients use the Balanced flex package, and only some use Granular. The Balanced flex package is the recommended starting composition for most enterprise clients. You can find more in our documentation:
How Should Services Be Deployed?
In a nutshell, the Balanced flex package is easier to maintain and requires fewer resources while Granular is is more complicated and uses much more resources.
For most clients, we recommend starting with balanced and only shifting away specific services as you have identified a benefit. Note that granular and balanced are just example configurations. Balanced was designed to be a general purpose, a good starting point. Granular is more of an example of the most extreme configuration. You may also find this blog useful: A Challenge with Microservices: Defining Boundaries - Broadleaf.
After having deployed Balanced and you’re in production and find the need to move some services to a granular configuration if the need arises, take a look at this for some guidance Broadleaf Dev Central