I'm looking as well. As with most products, the name on the label has some extra costs associated with it. A skimmer like BK is well built, but is it any more "well" built that an MRC probably not. But BK carries a premium price for the name and pump.
The latest and must have are cone skimmers. Nothing like keeping up with the Jone's Reef. Do they work better, I think there is some merit to it. Would I see a difference in a 58 gallon tank, initially probably, but it's not worth the extra to me. For 90 plus maybe, yes. BK/Vertex has a new line of cone skimmers out with a great pump on them. Aquarium Specialty and Premium Aquatics have special intro price for them. The are some links and reviews on RC, Reef Builders and Glass Box.
I think the biggest difference is the pump. After spending several hours looking and taking notes I feel that some of the extra costs is a good pump. I feel a pump can make or break the skimmer. JMHO..........