The bottom of the laptop doesn't get very hot (even on a heavy load), warm, but not uncomfortable hot. The top however, especially right above the keyboard does get really hot.
my initial experience with battery life is about 4 hours.
I have no MacBook Pro, but I have a MacBook. I use SMC fan control and CoolBook. With the help of these apps I have no issues with heat anymore.
By undervolting the CPU you can lower the power dissipation by 1/3. And this will of course give better battery life.