There's also a thread on Sharrow props in the Power Systems section -
https://www.trawlerforum.com/forums/s6/sharrow-props-diesel-outboards-64111.html
I hope to try a Sharrow prop on my new Helmsman 38 Sedan build. Like most things in life, it comes down to money. I don't know how much a Sharrow prop costs, other than comments about it being 'expensive.' Ideally I'd like to get both a Sharrow and a conventional prop and try both on the boat, which is the only way to determine if it's advantageous for my particular boat.
The tests to date look encouraging. Depending on the boat and speeds, about 20%-30% less slippage than a conventional prop, and 18%-46% better fuel efficiency. With diesel fuel prices likely to stay north of $5/gal for the rest of my life, even a 10% improvement in fuel efficiency would be worthwhile (again depending on the price of the prop).
FWIW, Captain Steve of BoatTest thinks the prop could particularly benefit semi-displacement hull types.
I agree that the design certainly looks more susceptible to damage than a conventional prop. With the 'blades' essentially being open loops, they're likely to fare worse in an impact. I also wouldn't rely on one of these if bluewater cruising in areas with limited or basic repair facilities. But for my coastal use in New England, a repair shop (or ability to ship the prop) shouldn't be hard to find (especially if I can also have a conventional prop as a spare).