I have the scissors and they work but I prefer using a steak knife. I hold the egg and slap the steak knife blade into it lengthwise and give it a saw or two, this splits the eggshell then I unfold it over the bowl or whatnot to have the egg insides plop down.
I found with the scissors, sometimes you had to shake them over the bowl to get the yolk to pop out which isn't a big deal, I just find the steak knife more efficient for me, plus I lay the shells on a paper towel to dry to feed back to the quail - egg membrane is insanely nutritious, there are actually human supplements with it that have been very effective for joint problems according to studies.