Malta versus Gibraltar as an Axis invasion target

Which would be harder for the Axis to crack, Malta or Gibraltar?

Both are formidable: Gibraltar combines rock defenses with easier British reinforcement, while Malta forces an exposed assault fleet to linger beside a heavily defended island.

Neither target offers a favorable assault. Gibraltar's terrain is extraordinarily strong, and Royal Navy forces can approach it relatively quickly from Britain and the Atlantic. Malta requires a landing on an island while the supporting fleet remains exposed nearby. Keeping Axis ships near Malta to support a faltering landing would advertise their position and invite British surface and carrier attack.