The Boo arc is overall a pretty solid and good piece of work, I'd say. It's well divided between serious and funny moments, and the episodes contain more foreshadowing than one would mostly imagine. It's also very nice how they handled Mr. Satan in th arc. His overall introduction as a boomer and a faker to him proving at the end, even through not conventional methods, to have in a way his worth was very well done and worked with... his overall participation in the arc was pretty neat. It had also some of the best character moments in the series, like Vegeta's recognisement and break down, plus one of the most unique vilains, which is found in fat Boo.