Advantages of SAP EP over other portals

Hi all.

I have 2 questions:

-> I would like to know the advantages of SAP EP over other portals like Weblogic and Websphere.

-> why will we be using NWDI, the transports earlier were to save the par to desk and then upload the

par to server & create iviews-which was working fine. What are benefits of using NWDI?

Thanks in advance to all

Karthika