I've tried them all (except the pink one. it's just too pink. i get headaches)
So far, Grayscale and Marine are my favories because they're the easiest on my eyes. haha.
Marine is my favorite. It's really calming and I like the colours. I like Ocean and Submarine, but I don't like my text lighter than the background. Occasionally I change to Ice Cold, but it's too cold for that right now.