Geordi, his visor can pick up on all sorts of things. He's operated on Data so often, and has often shown a capacity to apply theories across disciplines.
Scanning bone breaks and seeing them as engineering puzzles, repairing ruptures, understanding stresses, seeing heart beats and heat signatures....
...100% Geordi hands down. Plus he's good with people.
Of course in terms of real life, James Doohan (Scotty), as he's a WW2 veteran.