lots of our clients demand more than the available reporting features. We currently use Litmus for each of our deployments to provide the best reporting possible, which works fine, but it's a 3rd party service, which we have to pay for additionally. I think it's a no-brainer that Marketo should implement enhanced reporting capabilities like user client (desktop vs. mobile etc.), time spend reading an email etc. In addition to that, I think it'd help a lot users/customers if there would be more testing features like there are in litmus e.g. the link checker, subject line and spam checker and so on.