There are many factors that impact your battery life beyond which model Mac you have. See the BATTERY LIFE FROM A CHARGE section of the following link for details, including tips on how to maximize your battery life.
The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
what battery timer app do you use?I went from a 2012 MBA to the 13 rMBP. RMBP consistently outlasts the mana in my application. If I have the screen at 40% brightness and am working on a document and email and a little web browsing,mine battery timer shows over 9 hours. I have gone more than 8 hours regularly.
Search for "Battery Logger" in the app store. If gives you a full accounting of actual usage (deducting shutdown and sleep periods).what battery timer app do you use?
I went from a 2012 MBA to the 13 rMBP. RMBP consistently outlasts the mana in my application. If I have the screen at 40% brightness and am working on a document and email and a little web browsing,mine battery timer shows over 9 hours. I have gone more than 8 hours regularly.