What I like best is the way Portfolio makes it easy to catalog items, create web galleries, and manage metadata.
What I dislike is performance issues that you see when your catalogs get really big (1 million + assets).
Make sure you ask the right questions to the right people at Extensis when you are planning your system. The posted requirements would work fine for a small deployment, but across an enterprise, you will need a consultation to assure you will have a setup to handle your needs.
Do your homework concerning your actual planned usage. Portfolio will requires more resources than you may think, based upon the information easily available. More than a million assets and hundreds of Netpublish sites require serious dedicated hardware. And don't forget storage.
Portfolio allows for our photographers to quickly catalog their images and provide the customer with their finished images quickly, through a Netpublish site. It allows our archivist to add important metadata to images and publish a library of images for use across the enterprise. It allows various groups to provide access to event photos. The best part of this is it eliminates the duplication of images by keeping all of the images centrally located while allowing the images to be used in multiple ways.