The maximum "head lift" refers to the total height from the source of the water to the destination or discharge point.  The maximum "vertical suction lift" is the vertical distance from the water source to the pump. 

Most importantly: Will the unit be used for irrigation purposes, water removal, or both?  

The Water Transfer Pump is designed to move a large amount of water in close proximity to its source.  For example, if a flood causes an area to overflow, this pump is a good tool to remove as much water as possible.   

This pump can also be used for lawn and garden watering, pond/pool filling, and more.  It has a maximum "head" of 115 feet and a maximum vertical suction lift of 28 feet.  These are important specs to note when draining a basement or deep pond. 

The High-Pressure Irrigation Pump is used to move water farther and higher than typical pumps.  It's ideal for sprinkler systems and other irrigation application.  It can also be used for dust suppression, remote area firefighting, tank filling,  washing down equipment, and more. 

The best way to think about the High-Pressure Irrigation Pump is to picture a garden hose.  When water flows through it, the maximum amount of water that the water source can deliver is exiting the hose.  If the hose is bent and the water is restricted from exiting, pressure is created.  Although the volume/output is less, the distance you can discharge the water is a greater distance.  The High Pressure pump's internal valves and channels create the constrictions yet allow the pump to operate at temperatures that do not cause the pump to overheat and fail. 

Compared to the Water Transfer Pump, the maximum head lift is 220 feet, while the maximum suction lift is 26 feet. 

If you plan to use the pump for both irrigation and water removal, the High-Pressure Irrigation Pump is the best choice.