We are looking into upgrading our Campaign. What are some of the key benefits that v7 has over v6? How do the two version differ other than bug/issue fixes?
The main difference between v6 and v7 is that v7 offers a bridge to Campaign Standard with:
revamped UI (so that icons match between v7 and AC Standard)
built-in connector that allows to use v7 data with AC Standard capabilities for some of your use cases (improved MTA, consolidated Analytics reports, better integration with Adobe's clouds)
In terms of Security, a major flaw was discovered in v6.1.1 b8770 and below, a patch has been released, but this alone should be a reason to upgrade, along with loads of bug fixes, new features, security enhancements.