The good news for Mac users is that battery life is improved with Apple's
OS X 10.8.1 update, which attempts to address one of the biggest complaints with Mountain Lion. Unfortunately, tests around the Web show that battery life is only marginally improved, in some instances only adding two minutes of additional run time.
In depth benchmarks from The Mac Observer
show what can be expected with a heavy workload, and the result is that while OS X 10.8.1 offers better battery life than 10.8, it still trails 10.7.4 by 78 minutes.
"The battery life hit caused by 10.8 Mountain Lion is significant," TMO wrote. "Our 2011 MacBook Pro lost 2 hours and 10 minutes, or 33 percent, of battery operating time following the upgrade. Remove the Wi-Fi icon from the menu bar had no positive impact (in fact ,we actually lost 5 minutes of battery life)."
Similar tests from other sites reveal the same thing -- Mountain Lion is a bear on battery life, at least for now. Apple is said to be testing a new iteration, OS X 10.8.2, though it's unclear if battery life remains a focal point.