E10 is a slick easy to use tool that is also robust for those automation experts. Our event manager is up almost up to speed enough to run full campaigns in only a few weeks. For the power user it has excellent SFDC digital behavior tools where sales people can monitor every move their prospects make and get notified about it. Automated nurture streams, campaign management, open API's to most major vendors with cloud connectors that drop right into their "Campaign Canvas," and much much more make this the tool to have. I worked with Aprimo for 4 years and this is far above and beyond.
Room for Improvement:
Some times new features get rolled out too soon, but the good thing is they constantly adapt to the demands of their customers.
Eloqua is not just marketing automation, it is a powerful marketing network. Their community is so active with so many experts, being just a part of that is worth the money. I have become a better marketer because of the network Eloqua has provided for me.