I’m pretty sure Ghibli is one of the only studios on earth capable of taking a storyline like this one’s and making something worthwhile out of it. The plot has a kind of meandering, silly quality to it that could easily have turned to tedium, but no; from the seemingly boundless resources at Ghibli’s disposal, the studio makes the movie work as a creative, lighthearted, and ultimately endearing show.
Admittedly, the anime lacks some of the heartfelt poignancy found in some of the Ghibli’s better works (ie. Whisper of the Heart, My Neighbor Totoro, Spirited Away, etc.), but it’s difficult to fault a studio for occasionally making a movie that ISN'T incredibly ambitious. Like in Porco Rosso, another one of Ghibli’s somewhat overlooked films, the studio doesn’t try for a whole lot of deeper meaning, but manages to be fun anyway.
A primary, very simple joy of this anime can be found in the reappearance of the two characters from Whisper of the Heart. In WotH, The Baron was an immobile figurine, but played an important part in the main character’s spiritual growth. Here, he’s a fully fleshed out character, a lithe and haughty little creature who sparkles with originality. Along with his partner, Muta (also dramatically changed from WotH), they provide an excellent backbone to the show, and prevent the sometimes shaky storyline from ever becoming dull. The main character, in standard Ghibli fashion, is very likeable, albeit somewhat unmemorable.
The entire show is bright and colorful, with the standard attention to detail that Ghibli is so well known for. Character designs (excluding the traditionally normal protagonist) are memorable and quite excellent as a whole. However, compared to Spirited Away (which came directly afterwards) or Princess Mononoke (which preceded this), I was somewhat disappointed. The animation is still good, but just isn't quite as amazing as I've come to unfairly expect from the studio.
Sound as a whole is good; the background music is good at being exactly that, and the voice acting is noticeably above average (unlike Gambit at anidb, I absolutely loved The Baron's voice).
I’d definitely recommend that you watch Whisper of the Heart first; I got a lot of enjoyment out of the cameos, and WotH is quite simply a better film. However, even if you haven’t seen WotH, this movie is still well worth watching; there are plenty of laughs to be had, and The Baron is the coolest feline with a cane that you will ever see in your life, regardless of whether you know where he comes from or not.