Universal Containers is planning to migrate two million account records and 10 million contact records...

For migrating large volumes of data, such as two million accounts and ten million contacts, a third-party tool is recommended. Here’s why:

Scalability and Performance: Third-party ETL (Extract, Transform, Load) tools are optimized for handling large data migrations and can better manage the complexities and scale of Cloud Kicks' data migration requirements than standard Salesforce tools.

Data Quality and Transformation: These tools provide advanced capabilities for data cleansing, deduplication, and transformation, ensuring high data quality during migration.

Salesforce Best Practices: For large data sets, Salesforce advises using ETL tools that are specifically built to handle bulk data operations, as they offer better error handling, logging, and performance for large-scale migrations.