The 280 is not that fast and you are limited in seating capacity, and the fuel type is very expensive.
The 480 is more expensive, uses more fuel but it costs less.
You can calculate the 5 yr cost (say) based on published data taking into account this balance of fixed and variable costs.
It really depends if you want to carry more than 2 people and never more than a small amount of baggage.
A 280 at around £65K - 70K with good component times is probably quite a good deal if you dont want to go far or fast.
h-r