Are the pumps too powerful?

[bajaedition]

I have heard it said that pumps can damage the beer's flavor is some manner.

So that is why Budweiser taste so bad

 

[mredge73]

Using a pump during the sparge phase will always do more good than harm.
Think about what you are trying to do, you are trying to rinse sugar out of grain.
This takes physical work to do this; mixing, stirring, recirculating, etc...
There is a very minor concern with "hot side aeration" that I don't fully understand; just don't splash it a bunch and you should be fine.

Using a pump to transfer beer (post fermentation) is tricky. You don't want to introduce oxygen in or agitate the CO2 out of solution.
This is where using gravity to create a gentle siphon or pressure transfer is preferred.