Have you ever heard her as Yuuko in xxxHOLIC? (which also has Firo and Isaac's VA's, too. Tatum as his natural five-fathoms-deep voice). She's SO incredibly good that I've come across at least two reviews from notoriously dubs-suck people that say that everyone should watch xxxHOLIC in english at least once, purely for her performance.
This might sound bad, but one of the things I liked about Glass and Tatum being cast as Isaac and Miria, is that it gave them a chance to work on their chemistry, before taking up Triela and Hilshire in Gunslinger girl: il teatrino.