It really comes down to what you want. Boxes don't bitch, but then they don't mind going 160kts either. The Do228 is a nice machine and is great short field. but the CASA can lift more and take bigger things. The ramp is fantastic for loading large bulky items. If I was to sum up why not to get a Dornier, Twotter or Caravan. It would be that the CASA has that ramp. Oh and by the way littleMo Mongbwalu is 570m long.
Its all a compromise, you would just need calculate what your needs are and make the decision.
a
if it comes down to money, I think that most Do228's are pretty cheap, and good bang for your buck.
Ya