so mayalee shot,and boma maga/duranga(whichever has the HP for extra damage)

how are they?are they a serious pain to level up?is the output damage good on mayalee shot?worth the investment?also,I was thiniking of sticking with only fire and dark bullets for shotgun so I can spread those DOT se's nice and fast.any advice on that?I'm trying to keep the fortegunner build nice and simple to minimize the amount of excruciating pa levelling.

any help is appreciated.