There are long list of customer where Oracle WebCenter Portal was implemented and running live now. What feedback you need? You need to be more specific – in terms of the feedback you’re interested in.
Also, whether you’re simply interested in using out-of-the-box product feature, or you need customization or you simply want to use their framework and want to write your own custom application using the framework. Customization is little tough if you don’t have the right mix of skill-set in your team.