What are the differences between Lycoming and Continental engine designs? Inspired by a discussion in chat.

Most GA piston singles are powered by either Lycoming or Continental engines.
The engine designs used by both manufacturers are broadly similar (4-cycle, horizontally-opposed, gasoline-powered, air-cooled), and they're both generally available with either carburetors or fuel injection, but I know they're not "identical products".

What are some of the differences between the designs used by the two manufacturers, and what practical implications do those choices have for pilots?
Lycoming engines have the camshaft above the crankshaft, and Continental engines have the cam below the crankshaft.  This seems to keep the Conti cams better oiled and therefore less susceptible to corrosion.