Unless you're using monstrouslywide bars, I much prefer the drops in those situations. Better for everything except bunny hops, and even those the hoods are better than the flats IME.
During long descents on the road, having bartop levers adds a very comfortable alternative to the hooks. On a steep off-road descent or drop, using the tops allows you to put your weight significantly farther back than in the hooks. I prefer grabbing the bartop for dismounts rather than the left hood, the balance is slightly better being closer to the stem. For technical curvy sections, I agree that the hoods or hooks are better.
I'm not going to get evangelical about it, but I find bartop levers to be a very handy 90 grams to add to a cross bike. Are they absolutely necessary? Of course not. But despite their "unpro" appearance, many pros on both sides of the pond choose to use them; not just for cross, but also Paris-Roubaix and other cobbled classics.