A lot of the decision depends on the size of your tank, the bioload of the tank, your budget and future plans to upgrade.
Comparing ABC NW skimmer to XYZ NW skimmer is tough to do because most people only have one or the other. You can say, "I have "x" amount of gallons and want a skimmer that will handle a normal bioload for "x" amount of gallons". Then, we can give you some pointers.
However, in the real world, not many of us have tried 3 or 4 similar but different brand skimmers. A lot of people have probably used NW's and Beckett's, you can find a gazillion threads on that topic. Also, there are a lot of people that like to say their brand of skimmer is better than someone elses brand...those types of threads are 99.9% of the time pointless.
The key to choosing is to get the most bang for your buck from a reputable company that will stand behind the skimmer for both parts and customer service. Going too cheap is usually a mistake and unless you are a wealthy man, going too expensive is just out of the question. That leaves you with middle of the road skimmers...there are several companies out there that build decent skimmers. Choose a brand and research it thoroughly, see what the good aspects and bad aspects are, then look at the next brand and research it thoroughly.
You should be able to knock it down to just a couple by just doing some serious reading. It would help to see them in person if there is anyone in your area using something similar. It is your hard-earned money, so take the time to research it right instead of looking for a quick fix like you did with this thread saying rate these four skimmers now
