My neighbor is putting in a wood pellet fireplace insert. He insists that there are less emissions from wood pellets and even corn than cord wood. Is this true?

Yes it is true. The quality of the stove is such that it has a much better combustion process and burns much better. Cost of pellets are more however but the added efficency brings the cost of operation down to that of cord wood.
Another advantage of this is the auto feed that is provided with this type of unit. It keeps itself stoked for quite a long time, while traditional wood stove requires you to insert logs every few hours.