The Free online dictionary lists Life and Death as a variant of Life or Death.

To my mind when we use words like  **difference** **between**, the usage should be life **and** death. 

Here are two different usages:

Cancer patient says he is being made to make **life or death decision** after health plan cancelled.
(http://www.foxnews.com -Headline)

another way of saying this could be:

Cancer patient says he is being made to make a decision between life and death after health plan cancellation.