It looks good but I don't think that it's powerful than Zapier. Creating a workflow is harder than Zapier and integrations are not enough. I wanted to create a workflow that fetches data from an external RESTful API, parses the response and for each item of the response array performs another HTTP request and then finally merges the output the HTTP calls and sends a email to me. I'm not sure that this a common case but I can do it this in Zapier with Javascript and advanced transformation tool but I couldn't figure out how to create a workflow like this in Integromat.

You should really consider adding programming language support in order to be able to provide advanced features, otherwise it would be a service similar to IFTTT and I would pay it since IFTTT is free and easy to use.