[Silock]

I have the V and don't do reverse leg lifts. They're mostly a hip flexor and lower back exercise, not a lower abdominal exercise. Reverse crunches are way better, easier to maintain proper form on, and consequently are less likely to give you lower back pain (which is caused by fatiguing the lower back and over-strengthening the hip flexors that can happen with reverse leg lifts).

EDIT: Do them if you want. They're just not necessary to obtain that "V" shape. I would personally avoid them, much like I avoid movements with a lot of lower back flexion. The risks far outweigh the benefits.