That rather depends on the relative importance of various factors. My boss always says he can give you two of the three: load, speed and price. So which is important? A more detailed consideration, what is the relative importance of:
Price (always first thing to establish a boundary for. It will set the limit for the rest)
Comfort/space
Speed
Jet (many pax prefer to turboprop, even if the airborne times are little or no different and the jet smaller and thirstier)
Aircraft age
Field performance (if indeed it is a factor - will it always use major airports?)
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My preferred compromise for the above would be a Beech 350, but will it suit your people?