From all the tools I've seen, yours is really nice. It respects both the framework and the developer by not adding crappy custom CSS, using the framework as the official documentation mandates and prioritizes a sane workflow. Congrats!
Do you have any roadmap when it comes to more content? I think that's what is king with those tools. I use them because I don't want to hand-design markup for yet another pricing table or any other generic startup design component I need. I like being able to drag and drop them around, and then just go back to my backend code and make that shit work.
I would love to have a more extensive gallery, specially when it comes to items: search results, filtering, sorting, grid view, list view, swipers, etc.