I also considered both and bought south horizons. From news, Hang hua is dangerous when it is typhoon. In south horizons, typhoon 10 n I walked down and it was still safe and just felt more windy.
I guess future potential of south horizons is better after the mtr since it only takes 15 min to admiralty. Guess can attract those working in admiralty and central to move in.
Clubhouse is super good with very low cost facilities and classes for kids.