I bought the Braava in a combo pack with the Roomba. It works without any problems one after the other.
Technically, the Roomba is far superior (Wi-Fi, app function, IR sensors, room mapping, etc.). The Braava is simply a wet rag that systematically wipes the room damp.
I even seal the parquet with the Braava, 2ml Pakettmittel and rest of water in the attachment and the parquet shines again. Of course you can dust beforehand, but I wouldn't let it run at the same time. But Braava does dust too - it has two attachments for dry and damp.