I bought a Reef Octopus Diablo DC170 from Reef Supplies a couple of months ago. It is the best skimmer I have ever had! Admittedly my skimmer history isn't extensive... only Deltec MC600, SWC 160, and Vertex IN-80, but so far the DC170 blows them all away. I have never owned a BK so I'm not commenting at all on that brand.
1) It is quiet. I have mine on full blast and I can only hear the sound of it bubbling. If you listen inside the stand there is a slight humming sound. I do have my own silencer on the output... Reef Octopus skimmers tend to make splashing noises, but that is easy fixed.
2) It is my first "set and forget" skimmer. Very stable. It reliably skims all day without needing adjustments. Only the SWC 160 comes close in terms of consistency (in my experience).
3) Big skimmer cup.
4) The gate valve is so easy to adjust in small increments. The SWC's gate valve wasn't as easily adjustable (harder to turn)... and I won't even discuss how big of a pain it was to adjust the IN-80 and MC-600.
Hope that helps you make a decision. Personally I don't think the Reef Octopus POV skimmers are worth the extra money if space is not an issue.
I'll be the first to admit the controllability feature of the DC pump isn't highly useful however
don't think I have touched the controller for weeks now.