I have made this recipe twice and my family loves it. We have huge blackberry bushes so our berries are nice and fresh. However, I would recommend this: It is something that needs to be ate very shortly after making. I even used frozen berries the first time. I did whip by hand once and it seemed thicker than the time I used my stand mixer to whip. For a quick treat this is an awesome recipe.
This was a good dessert, but not great. Mine came out a little thin, despite having good peaks on the cream before folding in the berries. As it rested in the fridge, it lost its stiffness, and when we did go to eat it, it was really like the consistency of "cool whip" that has been left out on the counter for an hour or so...