I just started to use IBM RAD and IBM Websphere Portal few weeks back, IBM RAD is a very complete tool built on top of Eclipse, it has a lot of features that facilitates the work on portlet development, you can create in a few minutes a portlet using Struts or JSF as framework. Once a portlet is created you can build and package this portlet as WAR file to deploy on Websphere Portal.
Websphere Portal is completely updated portal solution, you can run JSR 168 and JSR 286 compliant portlets, you also have the option to create portlets using the IBM specific implementation that contains a lot of additional features.
The entire portal is fully customizable, you can change the portal appearance by adding new themes, all portlets can be added to a portal page by just drag and drop then on a page, access control can be easily done via deep integration with LDAP. You can even use google gadgets on your portal page!
Are you worried about scalability? Don’t worry, you can put several websphere portal instances running on a cluster mode.