Financial services company had decided to buy BEA Portal Server to build their customer site. It turned out that they were only using one portlet per page; of course it would have made so much more sense to just write the app as a normal webapp. Adding the complexity of the Portal software running on top of the app server running on top of the web server made development far more complex.
When you utilize a general purpose open source framework you often wind up with complexity and extra functionality you don’t need. Then when updates are made or you make customizations it’s hard to integrate them. Sometimes it might be abandoned and now you have to maintain it yourself when OS versions change or other needs appear. Now you have code you don’t really understand yet have to make potentially major architecture changes. It’s hard to balance the benefits and challenges especially if they might be far in the future.