If you're looking for an anime with quick-paced action and loads of screaming and fan-service, look elsewhere. If you seek an engrossing anime with meaning and a certain "sentimental" charm, Mushishi is the deal. While there's nothing totally wrong with the former type of anime, Mushishi really sets itself apart from the others - with a very melodic and abrupt opening, calm atmosphere and music throughout the show, as well as minimal dialogue that is quite monotone.
The story is a very interesting one that explores the world inhabited by creatures dubbed "Mushi", which surround us and are much more complex than any standard organism. We are introduced to an enigmatic man nicknamed "Ginko", who is a self-proclaimed "Mushi master" and seems to possess a considerable understanding of these perplexing creatures. Each episode is standalone and the series does not have any discernible ending, but this is a huge part of the charm of the series and that allows it to be easily picked up from any point. In each episode, Ginko meets individuals who have been affected by the Mushi in some way.
The dub is surprisingly great and lacks the melodramatic and over-the-top voice acting that other anime tend to have, so I would definitely recommend it just as much as the original. This is a great watch for viewers of virtually any age. What's more? It's great for stress and insomnia.