I have the JBJ 30g rimless and I have the Cadlightes pipeless skimmer and like it. I don't have room behind my tank so it had to be in one of the rear chambers. If you have room behind your tank, look into the Aquamaxx HOB skimmer. Great skimmer for HOBs. The CPR is ok but noisy.
One thing to consider with HOB skimmers is if the cup overflows. Do the skimmer cups have a way to drain back into the tank?