Ok, this is not intended to create a stir, but here goes:

If you fly correctly, and strive for perfection, then the main wing should have a slight positive AOA whith the plane on level ground.
This makes for a more realistic takeoff and landing. If you are not into realism, and you like "jerking" the plane off the ground, and require that the plane stay put once the wheels touch, then a slight negative AOA may be what is best for you.

All my planes have a positive AOA, (they are all tail draggers), and I make nice 3 point landings with all of them, (except the Texan).

If you have a negative AOA, the plane is much more prone to being flipped over in the event of a tail wind while taxiing.

It is mainly preference when it comes to the averagte .40 size plane.
Once you are in the air, the plane does not care what configuration your landing gear is.
Some small planes don't have any gear...

Bob