Hi Kevin,
Air source heat pumps work very well in modern new-build homes, provided that the building fabric is airtight and they are installed by a knowledgeable professional. Proper design and installation are key to ensuring they perform efficiently.
Most of the complaints about ASHPs tend to come from older, less well-insulated homes where heat loss reduces their effectiveness.
They also work best with an underfloor heating system rather than traditional radiators, so it’s worth factoring that into your budget if you haven’t already.
Best of luck with the project!