Motors make or break your AEG. Your M170 spring won't make a difference with a motor that groans when pulling an M120. Who cares if you have ultra high speed gears when your motor puts out 8 RPS with an M90. And a $40 piston alone won't get you that 450 FPS 35 RPS setup you've been dreaming of. The critical piece of any high performance setup is the motor.
These AEG motors advanced SHS upgrades into the toolboxes of techs around the world. Most technicians (the good ones at least) are familiar with the commanding power and blistering speed provided by SHS high torque and high speed motors.
What sets them apart? Obviously their high-performance is critical to their attractiveness. The utilization of neo-magnets provide the torque needed for high FPS setups. SHS high speed motors are known for being used in the craziest high speed setups. People often comment about their fast trigger response (especially the high torque motors). The pinion gears on them are possibly the best on the market. However their affordability separates them from the pack. You'll feel at ease after you purchase an SHS motor knowing how much you saved compared to buying other brands with similar performance.