I believe Play and SpringMVC are both great frameworks and it will be hard and probably too early to compare Micro with these two. I designed Micro's functionality from outside-in, and tweak it for performance from inside-out; small memory footprint, light and fast, .yml for config, extensions, routing and REST support without Java annotation, scripting support for fast prototyping, template engines for clean dynamic content manipulation. I am trying to bring in as much as I learned from my experience as a Sinatra/Merb developer.

Working with Designers for so many years, I was trying to build something that a Designer can use in minutes and use it for publishing his work with the littlest effort possible; all these without writing a single line of Java code. I am sure Play/SpringMVC can do that too?!

For Micro, the separation of roles and concerns is adamant. Micro (like jpublish.org) is about helping the publishers taking their dynamic content to the web as easy as possible, while allowing the Developers to bring in as much business logic power as possible but without interfering with the content publishing concern; the true separation of roles and concerns. Please have a look at Micro's documentation web site: http://micro-docs.simplegames.ca/ (source on Github too); hosted at Heroku, it is a Micro web app and its entire content is written in Markdown. This is an example of what most of the web Designers and the small publishers will like to have, I think/hope?! Speaking about the Heroku, the compiled slug size, for a standard web app using Micro, is 11.7Mb. Micro is micro :)