In a recent article, eWeek and the University of Wisconsin took a look at platforms for providing web based meetings.
The University of Wisconsin needs collaboration/meeting applications both for traditional meetings and e-learning. After testing a number of systems, price and confusing pricing models turned out to be among the biggest factors in making a final decision.
In addition to the general article, eWeek includes a detailed evaluation article, Striving to Make a Mark, and a one page 'scorecard' (eVal Scorecard: Virtual Meeting Collaboration)