This variation of the pullover produces constant tension similar to a variable resistance machine. It's also an excellent option for lifters who have excessive lordotic curvature throughout their spine. Even if that doesn't describe you, the exercise is a great core and upper body movement for thoroughly taxing the targeted musculature.
The key is to keep your core fully engaged throughout by trying to minimize the amount of arch produced in your lumbar spine and keeping the low back pushed into the floor, particularly in the contracted position.