Aside from Buffy's weird tendency to see competition in every woman Angel breathes in the vicinity of, it's a very fun episode, strong in both emotional stakes and breezy action.
The fantasy element is stronger than in early episodes of season 2, arguably it's the strongest we've seen it all season at this point. A costume store that makes people turn into their halloween costumes? Hell yes. Giles coming face to face with someone from his past and showing a new power level out of desperation? Hell yes. Willow becoming a literal ghost? Hell to the yes!
But we don't just want to watch anyone go through this, and the cast all give us strong reasons to care about their plights in this episode. Buffy's transformation into a brainless medieval woman is a fairly satisfying exercise in be-careful-what-you-wish-for.
But the real reason I love this episode is it finally gives Willow the moment she deserves. She is a beautiful, brave, smart, and funny young woman who up until this point had spent a season and a half unfairly being the butt of others' jokes. Here she is shining, leading essentially all of the heroes' actions and coming out of her shell with full confidence. Here's to hoping it's a sign of things to come.