vBooster Medical Plan and PRUHealth VHIS VIP Plan are both High-end VHIS plans; they differ in ward class, benefit limits, geographical coverage and premium.
PRUHealth VHIS VIP Plan's ward class depends on where you are hospitalised — HK / Macau / Mainland: Semi-Private Room; Rest of Asia: Standard Private Room; Outside Asia (accident): Standard Private Room.
vBooster Medical Plan suits you better if you value a lower entry premium (about HK$9,936/yr at age 40, non-smoker). PRUHealth VHIS VIP Plan suits you better if you value a higher annual benefit limit (HK$11,775,000) and a stated lifetime benefit cap (HK$54,950,000).
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.