We have been sailing the DS 12 under various conditions, everything from 0 to 25 knots of wind and as far as I can tell the boat is behaving well. It feels completely safe and easy to handle, no surprises there. I have still not managed to get some kids to sail it, so I can still not say how they feel about it.
As for the performance, (crew weight 75kgs) it doesn’t need much wind to get it up to 7,5-8,5 knots. The max speed logged with the GPS (no current) around 12 knots with only the main sail. We made a raid of 60 nautical miles with the “nice lady” on a Pixie 14 and it was a close race the Pixie a little bit faster (only main up).
It would be fun to have a V-shaped "old fassion" F12 made, as the F12 is underpowered I think it could put up a good race...