What arrangemet is better ? Why ?
Actually I have no idea which one is better.
The one with diagonals opening out up and out gfrom the center, number one.
By inspecting the members we immediately say that the diagonal members are 1.41 times longer than the horizontal and vertical members.
The longer members with the same cross-section perform better in tension than compression, due to slenderness factors and buckling concerns.
In the first configuration, the diagonals are under tension and will just need to be checked for pure tension.
In the second configuration, the diagonals are under compression, we would need to make sure the diagonals are strong against in-plane and out of plane buckling.