The ease of use, ability to quickly deploy new features, powerful UI customization options available and of course the support team.
Also they offer multiple payment options which can be really helpful if you are looking to build out your platform in a cost efficient manner without having to worry about the upfront development costs. The only downside with itgix is that their billing cycle time seems to be much longer than other similar services out there so you might want to consider doing some research on this before using them. They helped us create an automated system that allows our staff to more efficiently find data across the organization.