We‘be used Sena SP-10s for about 8 years (and hand signals for 15 years before that). Definitely prefer the headsets to hand signals when picking up a mooring because I’m also holding a boat hook. On a 55ft boat the helmsman loses sight of the morning at a considerable distance. We only use the headsets for docking in unusual situations.
As some mentioned, the Sena SP10 have a glitchy pairing routine (even previously paired headsets will sometimes not connect). But the Sena’s audio quality is amazing. It really is like you’re talking to someone right beside you in a quiet room. Stress levels aren’t much lower.
I just replaced the SP-10s with the new Sena Expand. This model seems to have solved the pairing issues. Startup is now reliable. They are also more compact and have better thought out controls.
SENA Expand Bluetooth Duplex Headset