I am not a big fan of portal software, because it is not cheap to delivery.
Portal specification is heavy to use and implement, and can have a reason only in very big corporate company.
SingleSignOn can be delivered in different and simpler way.
The big advanteg of the Portal is the ability to “deactivate” specific unstable feature on the fly, with also the ability to aggregate remote data (remote portlet is one of the key of the idea behind portal specification).
If you need to setup a fast demo, LifeRay is ready to use.