Welcome to TONMO, the premier cephalopod interest community, and birthplace of #WorldOctopusDay and #CephalopodAwarenessDays. Founded in 2000, we are a large community of experts, hobbyists and enthusiasts, some of whom come together when we host our biennial conference. To join in on the fun, sign up. You can also become a Supporter for just $50/year to remove all ads and enjoy other perks. Follow us on Twitter for more cephy goodness.
In theory they are pretty good, especially the new EX, with Quadri-helical injection :? . But I have not used one either.
I have used loads of different skimmers. The Deltec range is considered excellent, especially the APF600.
If you can't get hold of one of these then then Turboflotor Multi 1000 is the next best thing of an equivalent size.