Take a boat, let charters run 20-30 weeks a year for three to five years (or longer) and hand it over to a new company that may or may not update it.
The price is lower for a reason.

I would say the biggest question should be fleet and maintenance standards and service while on charter.

It has been years since I chartered with BVI YC, but as TW says, they charter individual boats so you could find out if the boat you plan to charter has been cared for.