Not knowing what engine you run, but for an aircraft engine, a manual pump has the advantage where if the battery or alternator takes a dump, the engine will still run if it has a manual pump (assuming said aircraft engine is equipped with mags). On a car motor, you don't have that advantage. I believe a manual pump lasts longer than an electric, and that's coming from a guy that runs an electric pump on my aircraft engine (my engine came from the factory fuel injected, so I don't have a provision for a manual pump). Electric pumps have come a long way, lots of boats run them with no issues. I do carry a spare electric pump with me, and so far in 4 years I've had my current boat, I've only used my spare to loan to others who were stranded. My old boat had both (4cyl Lycoming). I used the electric pump for starting the engine, and once started, shut the electric off and it ran off of the manual, that is the best of both worlds.