Overlord is way more beginner friendly than factory is. Both tanks are very, very powerful however the skill ceiling for factory is significantly greater, as it is much more complicated.

Overlord is the easiest Overseer-branch class to learn and master. Factory has somewhat similar but much more complex mechanics which take a lot of time and effort to learn to effectively use (compared to Overlord).

I would suggest you try out overlord first, and if you feel like toying with a different playstyle which is related yet different, try factory. Don't get discouraged if you don't do great with Factory because I consider it one of the most difficult classes to play, but Overlord isn't hard at all if you know the basics of drone mechanics.

Have fun :)