I’ve made mousse cakes quite a few times, and honestly most of them weren’t really up to my own standards. People eating them said they were fine, but there were a few things I knew needed work. Texture — sometimes too firm, sometimes too soft. The setting part is a pain to control. Flavor — if you use milk it tends to be too firm, because milk has way too much water. Time — making a mousse cake is time-consuming, and if you can’t manage your ingredients well, you won’t be efficient. So after summing things up, I’ve got some experience now, and I can make cakes I’m fairly happy with.