As far as I'm aware, zeit now can run server side code whereas netlify edge can only do at most some serverless functions, and is otherwise focused entirely on serving the front end
For instance Zeit can host a standard node server to serve your application if necessary https://zeit.co/docs/v2/deployments/official-builders/node-j...
Whereas on Zeit Now the root of the website can be a web server written in multiple languages, and offer the ability to make your own "Lambda Builder" if necessary https://zeit.co/docs/v2/deployments/builders/overview
/* /.netlify/functions/app/:splat 200!