I am by no means an expert on skimmers and my experience with my Reef Octopus is only about a month, but I LOVE it. I went from an Aqua C Remora Pro on my 75 gallon to a Reef Octopus SRO 2000 ext on my 125... This skimmer pulls out all sorts of yuck..and it is super easy to clean..my friend has a 180 gallon tank and he has the Reef Octopus SRO 3000 ext and loves it as well..
the only issue I (and he for that matter) had, was when you first set it up and plug it in, it overflowed with lots of foamy bubbles, very quickly.. He told me trick of putting a piece of electrical tape on the air intake pipe that worked for him and when I did it worked for me too.. once the skimmer brakes in, you remove the tape...(FYI, it is a little noisy with the tape on)
Good luck with your choice!