Which would you prefer? Olympus 75 1.8 vs canon 135L 2.0

I'm currently looking at the Olympus 75mm 1.8 lens for my omd-em5. The samples look pretty good, but now I'm wondering if I should just get a 135L for my 5d mark3. Anyone one out there have experience with both?

I know I may get some biased opinions here, but which set up would you rather use.  I shoot mainly portraits, behind the scenes, and landscapes. I will occasionally do some street photography. I love my 5d, but I'm really digging the bells and whistles and portability of my new omd-em5.

Opinions with some reasoning are appreciated!  Thanks!