I like both, but the OPI has a special pink microshimmer that makes it special. The NailNation is a bit sheer, but the holographic effect is very strong. Color wise, I think the pics are very accurate, they are very similar, and it's hard to tell them apart in the shade.
3 coats NailNation 3000 Max A Million (pinky and middle)
3 coats OPI DS Sapphire (ring and index)
no basecoat or topcoat in these pictures