Not enterprise kind-of large, but I'm in the process of building a booking web app (https://zapla.co) using React and Backbone Models/Collections.
I made the decision to switch from Backbone.View to React about ~2 weeks into the project, and so far I'm extremely pleased with it and have not regretted it! Unfortunately, the code isn't open source though.
What I've settled with for now is to attach an instance of the Model/Collection as a prop on the React component and syncing it to Reacts' state.
I do this by attaching a callback on the sync, add, change, remove events and use the the toJSON() method to copy it to the React state like so:
this.setState({data: this.props.model.toJSON()});
When saving a form, I have a method which handles the form submission. It copies over the state to the model and then saves it using:
this.props.model.set(this.state.data);
this.props.model.save();
In additional to this, I've built a tiny dispatcher to instantitiate my models and collections only once. In this way all parts of the app will always work on the same data and by in sync.
I made the decision to switch from Backbone.View to React about ~2 weeks into the project, and so far I'm extremely pleased with it and have not regretted it! Unfortunately, the code isn't open source though.