Julio, I've run a lot of different skimmers and there are obviously many ways to "skin the cat". What makes you unhappy with the ETSS? I will preface this with admitting that downdrafts are one of my least favorite skimming methods, but they can work. Is there a specific problem you are trying to address? I like recirculating needlewheels (I own both a Deltec and an ER RC), but it's not the one and only way to go. What makes one skimmer better than another is quite an individual choice. Becketts are very good for some people, albeit I don't see how a recirculating design couldn't make that even better.
So I guess what I'm asking, is why do you feel you need a more powerful skimmer?