When I had a bumper crop of Pickering and Angie, this is how I would freeze them. First peel, then slice them in half away from the seed, putting all in a big bowl. When done with that step, go back and cut the halves in pieces (roughly bitesize) onto a cookie sheet along with what you can salvage from the seeds. Freeze. When they're frozen, you can bag them and handle them easily. Fortunately I had a separate upright freezer with plenty of room for the cookie sheets. As mentioned above, it's best to use frozen mango in drinks, such as smoothies. And yes, I think it's worth the effort.