Great question. Beyond being on the cloud and everything that goes with that, I'd say that there are two fundamental differences with a product like SSIS.

1. Dataform focuses on transformations happening _inside_ the cloud data warehouse. We don't move data between systems. More and more businesses are moving from traditional ETL processes to ELT and centralising their raw data in their warehouse. Dataform help businesses manage the T in ELT.

2. Dataform is built with software engineering best practices in mind. In Dataform, all your transformations are written in code (mostly SQL) instead of a GUI like SSIS. The code can be version controlled, edited and fits better the large amount of transformations teams have to deal with.