How much does the flow rate matter?

[Peace River]

How much does the flow rate on a powerhead or a pump really matter? Is there a practical difference between a powerhead rated at 1200GPM versus 1600GPM? What about 2800GPM versus 3300GPM on a return pump? Does the difference in the nozzle matter more with a RFG? What about the difference between a standard powerhead versus a Sicce Voyager in the way it pushes water?

For whatever reason I really like the Sicce Voyager 4. It is an AC powerhead that just moves water and keeps running, however I recently got a Sicce 7 and was not particularly impressed with the performance or construction (which was weird to me because I have a lot of Sicce pumps starting with a .5 and going way up from there).

 

[Cichlid Dad]

I believe, right or wrong, flow rate doesn't matter nearly as much as type of flow coming from the power head or wave maker. Whether it is tight and say 20deg or so coming off of the head, or wide angle shooting out a wall of water and everything in-between.