I'm a bit of a noob when it comes to Japanese RPGs (most of my RPG experience has been with North American games such as Fallout and Bioware titles) but this is so far proving to be a very worthwhile purchase. With the involvement of Studio Ghibli, you get the same level of whimsy and wonder you get when watching their animé classics such as Princess Mononoke and Spirited Away, and the collecting aspect of familiars (think Pokémon...gotta catch 'em all) makes this game ripe for addiction potential. If you're an animé fan, that alone makes it worth the price of purchase, especially since it's a greatest hits title.
I'm not even 20% into the game (about 10 hours or so of gameplay) and I'm thoroughly enjoying it so far. The game is extremely dense in content and possibilities, making it possible to spend the equivalent of days playing it without unveiling all of the content. Visual design is beautiful to look at and the music is great. The writing is also pretty good.
As far as gameplay is concerned, while distinctive for mixing up turn-based and real-time combat, has a few problems that tend to be common to many games, especially those with a level and experience system. As the game has a lot of side quests, I haven't yet felt like I needed to grind in order to defeat a certain game area (i.e.: repetitive tasks in order to level up), although that aspect is still present. Also, boss battles are a source of frustration, which usually consist of a lot of running around and keeping your distance (but again, this is a problem common to a lot of games). A fast travel option is built into the game, but I haven't accessed it yet (apparently it takes about 20 hours of gameplay until you hit it), which is a pain when you have to travel between locations.
Otherwise, it's a beautifully crafted game that is definitely worth picking up if you haven't yet.