PlaceMaker can import the highest resolution and most recent imagery available from Mapbox.
PlaceMaker is able to seamlessly import the highest resolution tiles available over your entire area of interest (areas greater than 10km x 10km are possible) while SketchUp’s Add Location tool can only import a very small area at max zoom level.
The resolution and quality and the Mapbox imagery can vary depending on your location. The best way to compare is to order a Pay-As-You-Go license and a small amount of credits so you can test the imagery at your specific area of interest. Typically, the Mapbox imagery is as good or better quality than the DigitalGlobe imagery.