SE

Easier to set up and adjust for ride height and preload, especially since you don't have to worry about whether the shock height is too high/low for the height of the separate spring. One main flaw in a separate shock/spring design with lowered cars is the spring has a tendency to rattle in the lower arm if the shock isn't set up correctly. That and you can reduce shock travel if the shock isn't adjusted to where it should be.

Also it's a little easier to corner balance if you desire.