Hmm, the CMC Marine electric product does look interesting. Fighting off Naiad, TRAC and others in an EU patent dispute says something as well.
Their SE40 model is right-sized for boats the size most of us have.
.: CMC Marine - Stabilis Electra :.
It appears to have quite similar power requirements to a Seakeeper unit of similar capability. For overnight use, unless you had an enormous house bank, a genny is still required.
Wading through the ybw forum posts there seemed to be a view that fins have an edge over gyro underway, at least in testing conditions. The one thing that I would not like about electric fins, and perhaps hydraulic ones in zero speed mode as well, is the intermittent noise. Given that they will be close to the main stateroom, this would definitely be very disruptive for sleeping. A gyro further aft with a constant humming or whatever would be more conducive for sleeping I think.
I would not be without my Naiad's underway. But having something that works well and quietly at anchor also would be really good.