The website LaptopMag published a test of the new MacBook Pro 15" Unibody when running Mac OS X but also Windows. Results of the battery life evaluation in this test are particularly impressive.
They could surf on the web using wireless Wi-Fi connection for over 8 hours under mac OS X, a rather amazing performance level for a 15" MBP. If we were not convincing about this in-built battery technology when it was introduced with the MacBook Pro 17", current performance level indicate that it is the best solution.