Ease of use for all users (marketing and sales), the Eloqua online community makes it so easy to connect with other users, ability to automate our event processes, and it's FULL integration with Salesforce.com (our sales organization loves the behavior based information they have visibility to)
Room for Improvement:
Pricing - if you can swing it, Eloqua is worth it!;
Eloqua has always adapted to the needs of their customers which is visible on the new Eloqua 10 platform. We are in the process of switching to E10 and couldn't be more excited. Prior to Eloqua our processes were cumbersome and clunky. This tool made our marketers feel the power behind our campaigns and gave them the tools and confidence to execute campaigns themselves.