During sea trials once under way I ran some basic speed tests using Ookla.
Musashi 1 (PS) connected to the US datacentre hit a max speed of 90mbps down at approximately 15nm from the closest point of land.
Musashi 2 (SB) connected to the UK datacentre hit a max download speed of 222mbps at approximately the same range!
In reality of course it’s much further because they are connecting to cell towers further inland.