Unfortunately it doesn't break down their feature set. The case studies on Drupal.org will get into more specifics: drupal.org/cases
Also, none of those sites are likely to be cheap.
It might be wise to put in a caveat here: Drupal is wonderful system but one thing it's not is cheap. It's cheaper than many proprietary alternatives, but for a variety of reasons, the cost of getting help and training staff is considerable.
A site like this would probably cost between $10,000 and $20,000 with on-going support costs as needed.