Azure tables are cheaper, simpler and scale better than SQL Azure. SQL Azure is a managed SQL environment, multi-tenant in nature, so you should analyze if your performance requirements are fit for SQL Azure.
You can consider the following points to decide:
- Do you need to do complex joins and use secondary indexes? If yes, SQL Azure is the best option.
- Do you need stored procedures? If yes, SQL Azure.
- Do you need auto-scaling capabilities? Azure tables is the best option.
- Rows within an Azure table cannot exceed 4MB in size. If you need to store large data within a row, it is better to store it in blob storage and reference the blob's URI in the table row.
- Do you need to store massive amounts of semi-structured data? If yes, Azure tables are advantageous.