Two years ago, one of our biggest clients made a strategic decision to move their main code base from ATG to an open source platform, specifically Spring/Hibernate. This code base encompasses a number of portals addressing the needs of different types of constituents (Member, Provider, Producer and Employer).
Some of the elements of the project schedule were dictated by the fact that the key technology components used on the portals have been reaching the end-of-life (e.g. IBM WAS 6.0, ATG Relational Views, etc.). That is why the project was implemented in two phases – the Phase I focusing on the data layer and the technology update, and the Phase II focusing on removing the rest of the ATG framework including the migration of the front-end code base.