Really only difference is the height of the skimmer. They are both great skimmers in fact all the ASM's are. I mentioned the Octopus because its basically a cheap version of the ASM.
Octopus NW-150 Needlewheel Skimmer w/pump: Premium Aquatics
out of the two listed I would do this one if you have enough height in your sump
G-2
Specifications:
Body Size: 6 ½”
Height: 25
Foot Print: 10”X11”
Pump: Sedra 3500
Tank Size (Gal): 200 Gal