I think the reason the F27 Mk50 ended up with high wing was to stop the propellers banging on the ground when the aircraft was in it's Mk1 state (well, it was either that or a ten foot undercarriage and ladders to get in and out). When the F27 was designed (rumour has it for radial piston engines) the props where so large that the wing had to be on top of the fuselage. Later on, when Fokker "updated" the F27 (to the Mk50 - aka F50), the only person building engines of the right size was Pratt and Whitney with the PW127 and they came with in a package with six bladed props.
But the best reasons for high wings are for ground handling. No special equipment required (except for ground coolers on hot days). It also makes it more difficult for those on the ground to bump into things.
And six bladed props - they are pretty quiet and can still absorb the power put out by the engine. In CLB and CRZ I think they do 800 RPM.
But when you fly a F50, you can help but ask - where does all this power go? The ATR 72 has less, carries more, goes faster and burns less.