Fusion 40 or 30L for complete beginner

[Bodasifa]

I am brand new to marine aquariums and was looking at buying either a Fusion 40 or 30L. Is one better over the other for a complete beginner. I am leaning towards the 40 as it will have a greater front to back depth where i could keep my LR towards the rear and have more open space up front . I have done so much reading on keeping a salt water tank my brain is staring to hurt. any recommendations for a complete beginner is appreciated