The primary differentiator IMO is that delta sharing is an open protocol/standard for secure data sharing. This  eliminates vendor lock-in and enables diverse set of use cases.

The delta sharing repo explains the protocol and has a reference implementation

Also, unlike other servers, Delta Sharing internally uses pre-signed URLs to S3, GCS, or ADSL, so data transfer from a client happens at the bandwidth of the underlying cloud object-store. This way the Delta Sharing server scales extremely well and does not become the bottleneck.