I honestly can't pick one. Simba has different personality traits and behaviour in both stages of his life (Childhood and adulthood) and I feel that both are what makes Simba himself. In both ages, he has his carefree and playful personality but, when he is a cub, his arrogance and "show-off" traits are the most visible and we don't realize how courageous he
truly is until he becomes an adult. Yes, he did face those hyenas to protect Nala but it takes a lot more courage to take responsibility of something and "grow up". Both stages reveal Simba's true personality: this why I like both cub & adult Simba equality.