The ease of use for our customer support team in handling all of their accounts! I would like that they were able to have more advanced features or better reporting capabilities but there are options we can explore together with them so this isn't an issue right now.
They do offer many different ways you could customize your reports, it just takes some time getting used to how things work as opposed to other programs where everything has been preformatted by someone else's standards which makes finding what you want very difficult at first. We've seen significant improvements when comparing before implementation versus after implementing zeus into our organization.