I have one (young) right now. He hasn't played dead(yet) but he is very good at musking and hissing/puffing up. Which is probably why he is called the viperine snake.
I personally think they are beautiful, maybe even more than garters. Weird thing to say, but he looks much more 'at home' in his surroundings, unlike my parietalises.
Very subtle markings as well.
It eats like a pig, and just about everything too: cat food, fish, worms, pinkies etc.
According to the breeder I got it from,
maura is a very good fish hunter, which is why he recommends keeping them in an aquaterrarium.
This is his site:
Natrix maura - algemene informatie
It is in Dutch, but you will find some nice pictures of snakes/terraria.
Mine is the baby of the reddish/brown female of which you will find a picture on the site(huisvesting)