What is the difference between Crystal and Sophie Ash?

As Crystal, I write primarily why choose (reverse harem) series, meaning one female main character has 3-4 male love interests and she keeps them all. Although I do have a few standalones, most of my Crystal books are series covering a single storyline, so the books need to be read in order. 

As Sophie, my stories are M/F and are all standalone books. They can also be read in any order.