Another factor to consider is licensing. From Google Earth:
"If your business is looking to use Google Earth for any external purpose, you will need to license Google Earth Pro. Examples of external use include using imagery from Google Earth in reports and presentations or otherwise creating materials that will be displayed or distributed outside of your organization."
Often, however, the Google imagery for the US is from the NAIP program, which provides free county wide mosaics through the USDA Data Gateway, and often many state GIS sites will have that imagery (and others) available in different tiling formats for downloading, or in their own WMS services. GIS servers, such as the one at apfo.usda.gov also serve up NAIP imagery. ArcGIS online also has numerous imagery sources including NAIP.