Chubb VHIS - Standard Plan is the insurer's Standard VHIS plan (the regulatory floor of cover), while Chubb VHIS - Superb Plan is its flagship Flexi plan, which extends the ward class, benefit limits and geographical coverage above that floor.
Chubb VHIS - Standard Plan suits you better if you value a lower entry premium (about HK$3,634/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.