But are you using them in small tanks (20 and under)?
Yes, I use them in tanks from 10g-30g. I feed fine foods (crushed flake, those pearl jobbies, bbs, and veggie pellets). The reason I choose the pro line of sponges is that the openings in the cell of the sponge are coarser and less dense. This prevents them from occluding as fast.
regular hydro and typical sponge material:

pro line:

I also put a diffusor inside the body of hte sponge filter (to the bottom of where the airline attaches, there is a pic in my first link in my previous post showing this).
I really find the pro line to be far superior. I just bought all the replacement pro sponges from kensfish to replace my original series. The difference for me and the time it does to do maintenance (since I have them on 20 or so tanks) is phenomenal.