These work good for replacing the broken flange.
Just need to remove the old broken ring, when you are ready for tile and lay your hardibacker down. Just insert the new flange and screw it to the floor. Then tile up to it.
Will need to be sure pipe below is properly supported and not going to fall down when removing existing flange of course.
No input on the gasket, I just use a wax gasket with the rubber sleeve.
Never had a issue with them, is same my plumber uses .... could be better products available, just never had problem with old product.