Ghibli the Best contains selections from five instrumental albums from the Hacla label, conveniently compiled under the premise of a best album. "Best" is of course subjective but they have certainly managed to include many of the most famous themes from Studio Ghibli's array of animated films, ranging from the childish but memorable theme songs for Totoro and Ponyo, to Spirited Away's more elegant "Always with Me", to the poignant main themes for Laputa and Princess Mononoke.
Most of the source albums are specifically dedicated to a certain instrument (guitar, piano, cello and, yes, harmonica), and the album is in fact quite similar to your typical game piano collection in that the arrangements are often content to rest on the merits of their original melodies without making drastic changes. On the bright side they are not true solo performances, taking advantage of strings, percussion, and other accompaniment and carrying more weight than your typical piano collection as a result.
"If Wrapped in Kindness" from Kiki's Delivery Service is easily the highlight of the album, an earthy, folk instrumental of acoustic guitar, violin, and Native American percussion that patiently builds upon its source theme. The harmonica tracks show the greatest range in quality if for no reason other than the timbre of the instrument itself. It works quite effectively for the "lonely wanderer" sound in "Teru's Theme" and has some lovely violin accompaniment to boot, but it fails spectacularly at conveying the dignity of Princess Mononoke's themes.
Probably the greatest drawback to the album is that it suffers from so much competition from the many great Ghibli soundtracks and compilations already out there (Studio Ghibli Symphonic Collection in particular comes to mind). But for Ghibli fans looking to build upon their library of original soundtracks, image albums and song collections, Hacla's Ghibli the Best provides something different, if not entirely new.