Power tiller sounds cool but my money goes for an autopilot. Or tiller pilot.
One of the very best purchases I ever made for a boat was a tiller pilot!
In fact I recently just bought a used one from a member here for my C22.
Practical use includes using it to hold the boat into the wind while I raise or lower the main and jib. It is like a second person at the helm for you!
Other use is the simple freedom you get not being tied to the helm 100% of the time! Set the tiller pilot, and go sit on the bow! Or maybe have lunch, or whatever! I took our old 28'er from Everett to deep into Hood Canal a two day run in very calm conditions. I had just installed the new tiller pilot. I was absolutly thrilled to set the helm and go up to the bow with my boys ( they were very young back then ) and have a nice picnic dinner while the boat steered herself!
Hey Alan, you're going to be jealous when I get mine installed on Lady Jo!
Scott