Divshot supports Bootstrap, Foundation, and Ratchet (at present) and our new project structure works just like a folder on your hard drive. Because Divshot allows you to edit the entire HTML document you can actually build entire applications in it using a third party service like Firebase or Parse.
There are lots of smaller differences, but our focus on being a full development platform as opposed to a mockup/prototyping tool is probably one of the biggest.
No need to be sneaky about it. Adding the "FREE Plan" along side the other paying plans, instead of hiding it underneath, would help ease the feeling that they're solely out for my dollars.
We're still experimenting with the pricing signup flow, if it makes a large percentage of people feel there's no free plan then we'll change it (it's easy enough to do in Divshot anyway)