Please stop using the estimated run time as an accurate measure of remaining battery life. OS X only uses a time slice of recent prior use to guesstimate the remaining battery life. In other words, if you were encoding a video on Final Cut Pro for 20 minutes on battery power, then checked the remaining time, it would report something similarly low. Quit FCP and it will still only show a low amount of remaining time. Wait 20-30 minutes with the machine idle with only Mail or Safari or Pages open, then it'll go back up in estimated remaining time. However, if you have a background process doing something you don't know about (or have forgotten about), the estimate will go down.
It will fluctuate up and down depending on recent usage.
The only way to know for sure is to open the machine, look at a wall clock or your watch, then use the machine like you normally do until it stops running. Then look at the time again.
If you think you're going to get 9-10 hrs playing 3D games, you're sorely mistaken. But you will get much closer with text-based websites with low screen brightness, no backlighting of the keyboard, a strong wifi signal, and no background processes like malware checkers, big Time Machine or Carbon Copy Cloner backups, Handbrake encodes and etc. going wild.
If you actually use the computer, it will be less. Want 10 hrs? Let it sit idle and you'll get 10 hrs.
All that said, my new 15" gets excellent battery life. I charge it at night, take it work, use it during the day, take it home, use it at night, and put back on the charger at bed time.
