Wing mounted engines give a lot of advantages.
- First and foremost they reduce bending moments in the wings root. Alowing for a lighter wingbox or a heavier ZFM.
- Second they are mounted on a pylon quite forward of the wing which acts as a mass balance and helps mitigating high speed flutter. This allows for a less stiff (and thus lighter) wing construction. Ever noticed that wing on those airplanes bends quite a lot upwards while the tail engined airplanes have them almost rock solid?
- Third the fuel system can be smaller
- Fourth they are further from the cabin so less noise
- Fifth they are easier to access
- Sixth they are further apart so a failure of one engine is less dangerous to the other
- Seventh they don't have a wing forward of them so less problems with wing induced turbulence or with ice breaking from it during take-off.
- Eighth they sit below Center of pressure which in turn reduces the amount of downforce the elevator has to create during flight
- Ninth they sit closer to center of gravity which eases the loading process, reduces airplane inertia and reduces size of the elevator.
Soooo why bother with the tail mounted engine design?
Because it gives some operational advantages. (I would say they are very third world like)
- First the whole airframe can sit low, so you don't need stairs. Perfect for airports without any passenger infrastructure.
- Second the engines are mounted high so you don't need a sqeaky clean runway. (even a grass or water runway will do)
- Third the gear struts can be much shorter, so you can make a lighter landing gear (or make it much sturdier for the same mass)
- Fourth the rudder can be smaller along with lighter control lines. Although the vertical fin will still stay big.
Those are all of the advantages I can think of.