Pros and cons of a pull-push propeller configuration
Pusher-puller multi engine vs single or multi engine contra rotating propellers:

Pros:


Ideal configuration for a multi engine aircraft as it eliminates thrust asymmetry in the event of an engine failure.
As a consequence, improves safety during takeoff, landing and low speed, low altitude flight.
Can be a useful arrangement for multi engine flying boats.
Does not require oppositely geared engines nor heavy gearboxes.


Cons:


Engine crankshaft on the A/C centerline requires a more unorthodox airframe to accommodate which can present additional design challenges.
Does not fully eliminate propeller slipstream yaw depending on the aircraft layout.
Does not eliminate or reduce yaw from P-Factor.
Can be noisier inside the cabin than a twin with wing mounted engines.
Aft mounted Engine can be more difficult to cool due to indirect ram airflow.
Disrupted airflow from fwd propeller reduces the efficiency of the aft propeller.