Living in the area, I have heard all the negative comments about this, and it is pure NIMBYism and self interest driving the arguments. These same individuals would argue against new hydro lines, pipelines, or highways.
The biggest argument being made is how it may impact property values, and keep people from buying properties in the affected areas. They are valid concerns, but sometimes the greater good has to outweigh individual wants and desires.
These same individuals, especially along the proposed northern route, will be the same ones crying about wanting highway 7 to be twinned to reduce accidents and traffic.