the reason I was asking was they say the austrolop lays the most eggs a year like 300. . and I figured the sexlink would burnout quicker. so in the long run wouldn't the austrolop give you more eggs.
Yes and no... A Sexlink will burn out more quickly than a less productive layer which will lay longer, but you will get about the same number of eggs over the lifetime of the hen. Hens are born with a finite number of egg follicles, and when those run out will simply stop laying. If they lay 320+ a year you can expect about two years, and that's it; whereas if they lay 150-180 a year, you can expect about five years of decent laying.
It depends on what you want. If you plan on rotating out laying hens every 2 years, and if feed/egg ratio is important, than you want some of the production crosses like Gold Stars/Black Stars, Isa Browns, and even White Leghorns. If you want pet hens that will keep paying rent for years to come, I suggest a heritage breed or dual purpose, like Wellsumers or Wyandottes, as they can lay for years and years.