If my choice was between Pulte and KB Home, I would have to go with KB... Just comparing the methods of construction:
Pulte uses finger-jointed and glued 2x4 lumber on ALL vertical studs throughout their homes. Yes, technically it is No. 2 yellow pine, and yes it is technically one-piece lumber... It is scrap lumber that has been repurposed. KB Home uses single piece contiguous lumber on all 2x4 members of their homes. Not sure about you, but I want my 2x4s to be 2x4s.
Pulte also cuts corners (literally) when flashing their windows and bathtubs/showers. Not so with KB Home. They completely flash all water penetration points on their homes.
This may seem one-sided in my view, but I have owned several from both builder - I will never buy another Pulte/Centex home. Upon sale of my homes, the Pulte brand garnered me less of an ROI then KB by a wide margin.
I'll stick with the builder that has been in business for 60 years and is it's own warranty company.