Bupa MyBasic VHIS Plan is the insurer's Standard VHIS plan (the regulatory floor of cover), while Bupa Hero VHIS Plan - Core is its flagship Flexi plan, which extends the ward class, benefit limits and geographical coverage above that floor.
Bupa MyBasic VHIS Plan suits you better if you value a lower entry premium (about HK$4,796/yr at age 40, non-smoker). Bupa Hero VHIS Plan - Core suits you better if you value a higher annual benefit limit (HK$5,000,000).
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.