There is some similarity and there were some inspirations from Gmail to be sure. For example, there were many users of Superhuman or Front who really disliked the fact that they wouldn't be able to use autocompletions in their email client (we work on Superhuman in the browser and Front support is coming soon).
We do find that we are able to predict significantly more text than Gmail is able to.
We do find that we are able to predict significantly more text than Gmail is able to.