Superb Handling
The most beneficial aspect of a single wheel trailer versus a 2 wheel is the fact that it leans with you at all times. This allows the center of gravity to always be in the center, as it is on the bike. You feel no side force or pull while cornering, not even while braking in the corner!

It is easy to avoid road hazards and obstacles. This means that any debris that you miss with the bike will also miss the trailer.

The trailer is no wider than the bike, giving you better aerodynamics than a wide trailer will. If the bike fits through an opening, so will the trailer!