The APS looks just like a NAC7 with new colors. I also think you will find either of these too small for a 180g unless you are going to have a very small bio-load.
First let me tell you that I own a few of these and will give you my take on each.
The curve7 is great, very quiet, and well suited for about 75-100 gallons. (I've been running one on a 40b for a few years without problem).
The Curve 9 is a great skimmer that works very well - however it is pretty loud, and the pumps are crap. Last 1 year most of the time.
About 1 year ago I bought the Curve B-10 to put on a 400 total system gallons - this thing ROCKS! Very quiet and zero problems. The pump is a much improved design with beefy internals.
I would consider the Curve B-9 shown below on a 180 for the reasons listed above. I know it is listed as being good up to about 350g, but you will love this skimmer if you want to go with a BM.