Eggbeaters are generally much easier to make - it depends what methods you use. I get beaters cut from steel plate by water jetting and then have axles turned on each end by the same company - all I have to do is draw the part and throw cash at them . To make a beater yourself is still easier than a drum but requires a mill. If you use a hardened steel like Hardox (highly recommended), you will also need carbide cutters.

Beaters have other advantages over drums:
* one piece construction - no screws or welds to break.
* Higher kinetic energy for the same weight & diameter. The beater keeps most of its weight at the perimeter for efficiency.
* More tooth bite. The beater is usually better when going head-to-head against a similar drum.

The main disadvantage is poor aerodynamics. The beater acts like a fan and requires a larger motor and battery compared to a drum.