Donor Hub integrates with TNT, a software my organization uses to track donations received, actions taken with each contact/prospect, future actions to take, and the like. Specifically, Donor Hub syncs gift data, so I don't have to manually track down donations.
Donor Hub recently switched from a free service to a paid subscription, which was unexpected. Further, data goes through their servers, and as an organization we are not able to control that (especially with respect to security, though we've had no specific security issues).
Research what the needs of your staff are and compare features. There are other donation management systems out there, this is just the one my organization uses.
It allows for easier donation tracking for each of our staff members, which is especially helpful as they get busier in their missionary work, they probably aren't going to take time to track donations.