There's a bunch of import/export formats common to both Blender and Maya, but which of them support animation? FBX is supposed to, but for now our addon doesn't support that yet.
Specifically, I need to get animated cameras from a Maya scene into Blender.
One way would be to export a file for each frame (which would need markers and attaching cameras to them to make each frame's camera the active one for that frame) but that wouldn't work with motion blur.