Picked up the first box set at a local comic/anime shop on a whim. Really got into it. The Series is done quite well. In fact I recommend watching it under the choice of chronological order instead of broadcast order.
The series follows Itsuki Iba who takes over his father's company Astral. Its a small company of mages for hire. They have a very odd grouping with people practicing the following Magics: Celtic, Shinto, Omnyoudou, Singon Vajrayana (a from of Buddhism). Then they have a ghost with powers, and someone who uses Solomon's magic from another orginization. Itsuki has no magical abilites of his own, but posses an ability called Glam Sight. They start off doing odd jobs, but then things go from run of the mill business to someone contesting his presidency of Astral all the way to them saving and stopping a dragon. The series does wonders with character development and never left a feel of boredom at all.
The DVD box sets each come with a book around 150 pages that details out the myths, spell wave contamination, glam sight, the magics used in the series. In fact it covers them as religions first from a very objective standpoint and is quite informative.