The complexity of Eloqua can be difficult, particularly for beginner users. The more time you spend in Eloqua the more ability that you have.
Eloqua could definitely use an Intentional duplicate capability. This would allow companies to have multiple accounts/records listed under one email address and email based off of each of them separately.
Easy Nurturing: Marketo's solution for buckets of content seems much simpler and is a huge option for improvement in Eloqua. It is true that some of the complex Eloqua programs could be done much quicker with Marketo.
Visibility: It is sometimes difficult to track what is happening, where when you have a lot of communications. Particularly automation as it gets buried with all of the other campaigns for one off or just a few emails. Could be nice to have automation/nurturing be its own section that is easier to monitor, maintain and report on.
Eloqua allows us to automate many of the communications that a rep would normally have to do personally. This saves time for account and sales teams to be able to focus on serving the clients or selling.
Eloqua also allows us to automate nurturing, onboarding and winback campaigns.
Eloqua can sometimes be slow with a very large database. i have not found a solution that allows any additional speed for the size of our database, but occasionally it does slow user productivity while waiting for steps to complete.
The key here is to determine what their use of the product is. Someone with smaller needs likely does not need Eloqua. Depending on how they use Eloqua would change what I would recommend. I would be more than happy to recommend Eloqua to someone with the exact right needs.
Currently we have many programs set up in Eloqua. It is a complex system and so it will take a long time to get setup on a new system. There is also a fear that some stuff wouldn't be able to be transitioned and how to do redirects/be sure that everything is moved in time to prevent user issues. Eloqua does seem to be a rather expensive solution though, so that alone always makes it a possible reason to switch.