I rode a first generation one on the Velo Vision SPEZI trip two years back, and personally detested it. That may have been mostly to do with the coaster brake fitted, which applied itself whenever I freewheeled, because I discovered that whenever I freewheel, I backpedal very slightly at first. Add that to unfamiliarity with German roads and trying to concentrate on staying on the correct side, and it was nervewracking.
It was also a bit squirmy on a beaten dirt path - slightly better on tarmac. I rode it to the show from the bus, and got someone else to swap with me and ride it back. They hated it too.