Ok that's all well and good for items that are marginally useful. However, you have to realize there are several aspects items are chosen for. Reasonably, we could assume they are for survivability, killing power, and various basing uses, such as prevention of leakers or leaking. The difference between items is how effectively they do this, with how much energy, and how quickly etc. Most items balance these characteristics out, which is why some people prefer other items. However, there are some items that are outclassed in all of these categories. Look at the example of entropy. What use do you see for it? What build is entropy invaluable for? What about arcfire array? What does arcfire outclass? What situations is it more useful than gauss? What about gigajoule versus shredder?