Questions about Sega CD / Saturn memory carts

[Cinder6]

I have just a couple questions about the Sega CD and (official) Saturn memory carts.

Do they work the same? (As in, does the SCD one support direct saving?) Does the SCD one work with all games? Do they use battery backup?

EDIT: Note for people coming into the thread. This topic is almost a year old, and my questions have been answered. There's a new discussion going on at the end, though.