It's really a matter of personal preference I think, but me personally? I prefer and only use layer crumbles. I've just always had it in the back of my mind .. "all those pellets going down into their crop like little bullets...hmmmmm"
I would say try them both and see what your birds like better. Some people swear by pellets as being less wasteful, I had the opposite experience. My birds hated them, especially my smaller bantams, and they threw them everywhere looking for something else. Gave them their crumbles back, happy birds, no more food on the floor. Bored birds will also waste more food then busy birds with room to roam. My birds only go into the coop to eat then they are back out to the pasture, so they don't entertain themselves with sorting and billing food out onto the floor.