Bupa Hero VHIS Plan - Core and Chubb VHIS - Superb Plan are both High-end VHIS plans; they differ in ward class, benefit limits, geographical coverage and premium.
Bupa Hero VHIS Plan - Core suits you better if you value a lower entry premium (about HK$10,532/yr at age 40, non-smoker). Chubb VHIS - Superb Plan suits you better if you value a higher annual benefit limit (HK$6,000,000).
Neither plan is categorically better — your choice should rest on your own budget, where you expect to seek treatment and your family needs, ideally after a financial needs analysis.