The downside is the effort needed to manage the often cumbersome interface between the HRIS system and the Payroll system. Being without an interface is even worse, since the Human Resources and Payroll systems must then spend the organization's resources entering duplicate data onto the two systems. There's a very wide spread in the cost of Human Resources Information Systems. The more costly systems are the most comprehensive and flexible systems. No system comes out of the box in exactly the right configuration that an organization needs.
Every organization has a unique set of needs.
Therefore, a system will require some customization for optimal use by the organization. The more flexible the system, the more simple it is to customize. Customizing inflexible systems could render them inoperable or make them impossible to upgrade. The system will be more supportable if it uses a popular database platform and operating system. Determine what support the software vendor can provide, what in-house support is available, and what support is needed to install and maintain the system.