Madame Xanadu was one of my favorite new Vertigo series. It sort of foreshadowed the reintegration of the Vertigo characters with the DC universe as it featured appearances of by numerous DC characters (Entrigan, the Spectre, Zatara, Martian Manhunter) and referenced even more. I enjoyed the overarching plot of the first 10 issues featuring the love/hate relationship of Xanadu and the Phantom Stranger as they encounter each other in various time periods and Xanadu rebels against the Stranger's cryptic manipulations.
While Matt Wagner's plots are interesting, it is Amy Reeder Hadley's art that brings the book to life. Hadley is clearly manga influenced but not in the cartoony way of say Joe Madureira. Manga artists manage to convey a wealth of emotions through facial expressions within a limited palate of simplified cartoon faces. This is where Hadley's manga influence shows. Hadley's work reminds me a little of Alan Davis in the sense that it is mostly fluid curves and very few straight lines.