No'l makes an excellent point, gauge is only one part of it. Having just recently went through the tedious exercise of selecting armour myself, you really have to know what your goals and priorities are, because everyone's different and there is no "one" armour that is the be all and all. So many good makers out there and they all have their tiny differences. How important are things like quality, price, durability, screen accuracy? Also, is it readily available? How difficult is it to assemble? What is best for your body type etc.
You really can't get too much info on the subject, this forum and the great guys/gals on here are a tremendous help.
In the end I decided on AP because of it's reputation, quality, screen accuracy (aiming for EIB) and to boot he's a fellow Canuck, so you can't beat that
Hope that helps,