Standard Distribution plan is good if
- Your book is not in a price-sensitive market, or
- You don't mind lower royalties to keep the price low, or
- You are experimenting with distribution and not yet ready to make upfront investment in inventory.
Premium plans are good if
- You want to lower the price of your book, or
- You want to earn higher royalties, or
- You are sure of the book's market potential and don't mind investing upfront to increase your returns.
The choice between Premium - 200 and Premium - 600 depends on what your price and royalty goals are and how much upfront investment you are comfortable making.