I currently use the paid version of Mindmeister but am looking for alternatives. Apparently, Coggle integrates "seamlessly" with Google Drive. That would be great, but I can't find out HOW it does this after creating my first map. A Google search brings up nothing, and the "support" page (which it says I should look at if I have any questions) doesn't address it, and there's no obvious way to email the developers. The "We suggest you contact the developer" link above doesn't do anything apart from take you to a website that doesn't let you contact anyone.
Pity - it might be a good app, but without any useful supporting documentation it's unusable. I'm happy to pay for a good product, but not one that has no support available.