You have to remember these apps are not pulling imaging from a single source for the nation. It’s thousand and thousands of arial surveys, sat imagery, and (in SF case) UAV imagery. Yes it varies in quality with regions based on availability, weather when it was taken, modality etc. but what I look for, as stated above, is multiple different images and dates available for a given area to be available in an app. In this regard, SF dominates at the moment. Imagery resolution difference between apps is constantly in flux as areas are updated, which is usually done in an automated fashion since no one can manually review every county and survey in the nations