It runs OS X. Not only is it more secure and stable than Windows, but it also has better power management.
Better power management? Yes.
More stable than Windows 7? Hell no.
The only BSODs i have seen in windows for years have been hardware-failure related, or cheap crappy hardware/driver related. Put windows on decent hardware (with MS-blessed signed drivers), and it is 100% solid.
My MBP, running Lion, occasionally has to be force re-started due to the keyboard not working properly after some apps, or finder beachballing forever. My hardware is fine, but Lion is not.
I've had no such issues of that nature with windows since Windows 2000.
OS X is great, don't get me wrong (and I prefer running it to windows for a variety of other reasons), but the "windows is unstable!" crap went out the door with Windows 98 about 12 years ago. Flogging that dead horse just makes you look like a fanboi.