What challenges arose migrating from SQL Server DW to Snowflake/BigQuery?

[EvelynR]

My team is planning to migrate our on-premise data warehouse to a cloud solution, and we're evaluating Snowflake versus Google BigQuery. Our current setup is a traditional SQL Server data warehouse that's become too slow and expensive to maintain, and we need better support for semi-structured data like JSON logs. The main use cases are for our business intelligence dashboards and feeding machine learning models. For teams who have made a similar move, what were the biggest unexpected challenges you faced regarding data migration, cost management, or performance tuning in the cloud? I'm particularly concerned about managing egress costs and setting up effective data governance from the start.