In the bottle they don't look very different, especially in the sunlight. The Craze version looks a teeny bit darker.
On the nail, however, in sunlight, you can see a vast different starting. The Craze version is indeed a deeper orange, leaning toward some red. It also has a shimmer running through it. The Fast Dry version is lighter and glitterier (is that a word?). It was jam packed with glitter. I'm thinking both polishes took four coats - the Craze version because the formula is thinner; and the Fast Dry version because the color is more sheer.I do like them both, so I can see many manis in the future involving them both. Maybe layering the Fast Dry over the Craze version?
**DISCLAIMER** I was not paid for this review by anyone. I either purchased these polishes myself or were given gifts as friends because I could not find the particular shade I wanted myself. I am not a professional nail tech, nor do I want to be. I'm just someone who enjoys polishing my own nails :)