Ultipro is a highly rated SaaS payroll system that comes with many additional modules you can add to it, Like "Time and Attendance", (UTA) and can be a very expensive proposition for many companies. You may also find some hidden costs associated with your move to UltiPro that you didn't expect. For example, if you are one of those companies that have proprietary software and databases integrated into your current payroll system, you may be looking at several weeks of modification expense, depending on how complex your system is.
Another issue is: "How to keep data updated as new employees start at your company?" The Ultimate project managers will tell you that hiring Data Entry clerks is the way most companies will go. Of course you can estimate spending several thousands a month in hiring temporary encoders. After the "Go Live", you won't need to worry about maintaining two systems for parallel testing, but if you have many managers and employees numbering into the thousands, then you have an additional expense, heavy data maintenance. So expect to hire more people for the maintenance needs of UltiPro.
Ultipro is pretty good as commercial SaaS software is concerned, but it is only on a complexity of level 5 out of 7 on the "Romero Automation Complexity Scale". It is mostly weighted on the back end which accommodates their data transmission, but not so much help for your maintenance.
One example you may not anticipate, is that when a manager is transferred from one store to another, you will need to also change the supervisor id of all employes at that new store one employee at a time. You could add a procedure to update those employees on your local system, then upload the supervisor changes to UltiPro, but you will still need to use an wizard to import the list from a csv file into the Ultipro database.
Overall UltiPro is very reliable and scaleable for integrating additional modules to your core payroll platform.