Differences between eZ publish 2.x and 3.x

eZ publish 2.2 and 3.x are two different systems. The 2.2 version was a fixed solution with a fixed set of functionality and modules while eZ publish 3 offers much more functionality, flexibility and scalability for the users. eZ publish 3 is also a powerful development framework that offers the users a wide range of possibilities in terms of usage. If you have tried both systems you will easily see the differences between the two systems. Sitepoint.com has written a good article about these issues here