Thanks to your post, I made one of these several years ago GW!
It really is a help upwind in light airs. However....
In gusts like we're having here atm (last night > 60 knts) I'm not sailing at all, never mind trying to go faster!!!
In fact, I walked out at low tide today, to check my boat/mooring, and found 4 links on my Chinese stainless "storm chain" fractured, apparently due to the shock loads experienced last night.
Boat otherwise aok!