The retina mbp have same battery life as the regular mbp even with larger battery (on Apple site). I can get 8hrs with retina doing normal office work, web browsing on wifi and 50% brightness. If using the 650m graphic card (running virtual windows) 6hrs is the best I got, lastly playing HD videos will drain the battery in 3 to 4 hrs (66-75% brightness).
True. I'm sure as Apple continues to debug ML, it will only get better. I'm going to wait & watch. Perhaps by 10.8.4, it will be sorted out enough to reduce the annoyances. Refinement is an Apple specialty.