&gt;&gt; Battery longevity is what matters. I wouldn&#x27;t mind the smallest battery in the world if it powers my device the longest.<p>Nobody would mind that. But today, a bigger battery is more likely to power your device longer, all other things being equal.<p>If the Retina MBP&#x27;s guts were put in a 2012-style unibody and the extra space was simply filled with more battery, I tend to think that the Retina MBP&#x27;s battery life would be crazy good. And there are a lot of &quot;pros&quot; who use power-sucking, CPU intensive apps that would appreciate that.