Virtual On Oratorio Tangram is soon making its way to the XBox Live Arcade, which is good news for Virtual On and Sega fans. The series has been pretty low-profile since the release of Marz on the PS2. And for good reason, too: Marz is a pretty poor game.
Interestingly enough, its version 5.66 that's being ported over, which is the final arcade release. Compare that to version 5.45 that the Dreamcast used.
(If you're wondering what happened to the earlier versions, they were different play mechanics for Tangram that were ultimately rejected before the game was released. One involved fighting in only floorless stages, similar to the game's final battle.)
GameSetWatch's Robot-chan! column has an excellent run down on all of the past VO games and insight on how this new port will affect the series.