The skimz SK181 is a great skimmer for sure. Just not a lot of them out there. The NAc 7 and the xp 2000 are good as well and each has its place. The nac 7 is a nice skimmer for a more budget minded reefer. The xp2000 has a little nicer transition to the neck and pulls more air and water than the nac7. The sk 181 kind of sits in the middle of these two when you look at the specs. But is closer to the xp 2000. However the skimz line needs to be out longer to prove themselves here in the states. THe es 2800 pump on the sk 201 I had was a little loud for my liking. Louder than the bb2000 pump. the es 2000 pump on the sk181 had been reported to be more quiet.
I hope that info helps. I like the design of the Skimz. But like the performance of the BB 2000 pump....