I also done both and had success with both. I've recently done some testing using a formed thread tap. IMO, I think they provide a tigher thread pattern in printed parts. The cut threads work, but they can have more runout when tapping by hand.
Com'on Dean.... Its a SlingShot with RoadRunner sponsons. NOT a RoadRunner with a SlingShot Tub not build per the supplied instructions. Anyone can see that!