on the water valves I will use the Generic IF it is manufactured by the same company as the OEM . Some of the Whirlpool generic timers are made by the same people that do the OEM also . Sometimes we order the Generic and get the OEM packaged items
If there is just a little difference between the OEM and Generic we go with OEM or if we have issues out of a generic we go with the OEM ( or another Generic) . As dab147315 said " Good , Bad and Ugly"