How many times can you reload brass?
Anywhere from a few to hundreds of times. Light plinking loads give brass an almost infinite life span. Hi pressure loads can kill brass in just a few shots.
How many times can you reload shotshells?
Again, depends on the loads and pressures involved. Anywhere from a few times to a couple of dozen.
And which one is easier reloading brass or shotshells?
Depends on the equipment used, shell caliber, and the components. Shotshells and pistol calibers are about the same amount of effort using a single stage press. Rifle requires a bit more care and handling.