I've flown myself (and the family) over Disney and it's massive so bear in mind if the price is very low for the helicopter flight then you may only get to see the southern parts of Disney e.g. Downtown Disney, MGM and Epcot and maybe not the northerly end like the Magic Kingdom.

I'd recommend keeping away from Animal Kingdom as it's not fair on the animals with all the noise at the low levels the helicopters fly at and there is not much to see as it's very leafy. The FAA charts recommended at least 2000 feet over AK when I did it.