There are two main distinctions between electronic LED drivers: Constant current vs. Constant voltage. You should pick your LED driver depending on the electrical requirements of your LED system.
Constant Voltage LED drivers supply a fixed voltage, usually 12VDC or 24VDC, and use a series of resistors or built-in regulators.
Constant Current LED drivers fix the current supplied to the light fixture, but allows the voltage to vary depending on the load.
Since not all LED drivers are created equally, the quality of your power supply will have a significant impact on the efficiency and lifetime of your LEDs. To make sure that your light has a steady lumen output and no variation, make sure you are using the right kind of driver. Finding the right one depends on the constant voltage or constant current output and the total wattage of your system.
One very important note. No matter which kind of driver you choose, the total wattage of the light fixtures connected to the driver should never exceed the its maximum wattage rating.