Tina is designed to give editors the live editing experience they want (similar to a site builder like squarespace) while developers maintain control over the project. NetlifyCMS is missing the former. They have their preview templates but it is not an exact representation and requires extra work from the developer.

Tina is also designed so that you can create the editing experience that your customers/clients/coworkers need. Instead of a one-size-fits-all solution, you can give them something that is tailored to their needs.

As well, at the moment Tina only works with git (similar to NetlifyCMS) but we are working on other data source plugins as well (think Contentful, Headless Wordpress, etc).