Rain can vary significantly across a county. Look at the map view for your county on CoCoRaHS.org for a rainy day and see the variation. CoCoRaHS stations are not part of CWOP so not available for rachio but they do show the variability of rain in an area. Their gauges are typically not automated so more accurate. My gauges are usually very close unless we have snow or freezing rain.
As others have said your mileage may vary when using a PWS. It depends on the station and the owner's efforts to make sure it is reporting accurately.
I would not worry too much about which you select but if your are concerned then consider your own PWS.