I have the RW-4 in my tank, and it provides great flow. I run the W1 program (short pulse with the dial on the 8th line) - this gives me a decent wave, and my frogspawn loves the sway!
More wave setting options than you could ever need. Pretty quiet.
Not too bad for what you pay.
Have 4 in my tank, never failed. Low noise.
for the price can't complain