Motherduck is hosting duckdb in cloud. DuckLake is a much more open system.

Ducklake you can build petabyte scale warehouse with multiple readers and writer instances, all transactional on your s3, on your ec2 instances.

Motherduck has limitations like only one writer instance. Read replicas can be 1m behind (not transactional).

Having different instances concurrently writing to different tables is not possible.

Ducklake gives proper separation of compute and storage with a transactional metadata layer.

For what it's worth, MotherDuck and DuckLake will play together very nicely. You will be able to have your MotherDuck data stored in DuckLake, improving scalability, concurrency, and consistency while also giving access to the underlying data to third-party tools. We've been working on this for the last couple of months, and will share more soon.

i think a way to see it is MotherDuck is a service to just throw your data at at they will sort it (using duckdb underneath) and you can use DuckDB to iterface with your data. But if you want to be more "lakehouse" or maybe down the line there are more integrations with DuckLake ir you want data to be stored in a blob storage, you can use DuckLake with MotherDuck as the metadata store.