I bought the 200L for the front and I am very pleased with it. $169 is a lot of money for a light (I bought just before the weekend sale) but having a good light has opened up a new world for me.
I've thought about getting the rear light, but 99% of my riding is on rural roads where there is no extraneous lighting. It's just me, and the dark, and an occasional pickup truck coming at me or passing me. I have a Planet Bike super flash blinky. I think that makes me stand out in the dark from behind.
I like the 200L because I need to see what's ahead of me. I don't need to see behind me. I could see if I rode in a city where I need to stand out from storelights, car lights, etc., but I don't.
So, do most of you get the rear light because you ride in a "lit-up" environment and you need to stand out?
P.S. I've thought about getting a reflective vest to supplement my safety gear. Should be cheaper than another Dinotte light.