Here's a
characters/seiyuus page, with pics of the six main characters and their seiyuus, and some info about the seiyuus.
Sakurai Takahiro (most famous role, Suzaku in
Code Geass) was
persona non grata in the industry for a brief period a few years ago, after he was found to have plagiarized in a stage play he was putting on. But he's too good to leave on the sidelines, and he is now getting plenty of roles. He's just about as good as a seiyuu gets, in my opinion. I thought he was outstanding as the shady operator in
House of Five Leaves.
The rest of the main cast may not be as famous, but they are all names of interest. Ishihara Kaori is shooting toward the top right now, with roles in four shows this season. Taketatsu Ayana is already at the top, as one of the go-to moe voices. Sakura Ayane has a short but starry resume, starting with Merry in
Dream-Eater Merry, and with three roles this season. Hidaka Rina was a busy child actress, and recently has had a string of strong seiyuu roles, including Ririchiyo in
Inu x Boku. Oogame Asuka is not quite in the same league, but did do a convincing job as Erio in
Denpa Onna.