While I generally prefer the Ranma manga, there are some instances where I prefer the anime. For example, Gosunkugi and Kodachi were much more likeable in the anime, and both characters had episodes dedicated to them which were pretty nice. Artwork in the anime in the later seasons suffered greatly.
As for SM, I prefer the anime. The feel is completely different. It's CAMPY, which makes it memorable, at least to me and the people I know in real life (especially those who watched the localized version, which turns the camp dial up to 11). Besides the artwork in the manga is... kinda bad.
"So Igor wasn't kidding. Most people just ensure they won't die cold and alone by making friends...I gain superpowers and have mysterious voices tell me I did a good job. My life is a goddamn mess."
-- Minato Arisato, My Life is a Goddamn Mess