Functionally there is no difference at all. My heavy duty Cabela's electric and an old manual have the same stuff on the business end. They all have a corkscrew to push the meat to a spinning blade to cut the meat against a plate with holes that the cuttings get pushed through. The only difference is what turns the corkscrew. For an electric, it is the strength and gearing that turn the corkscrew that makes the difference. For a manual, it is the strength of your arm.
The real advantage of a good electric is the speed. I can drop very large chunks of meat in it and it muscles through them with no problem. I also have a cheap harbor freight (central machinery) beat saw that I modified. It came with a grinder that was attached to the same motor that drives the bandsaw wheels. I had to chop the meat into finer chunks when using it and still often had to take it apart to clear clogs it could not handle. The big electric has a reverse on it. I rarely get a clog, but when I do, the reverse clears it immediately.
I can do in about 10 minutes with the electric what would take me several hours with a manual. If you have the time, a manual should do the job for you.
Thanks,
Jack