How does Apple achieve such an ultra fast boot up? I'm a recent Mac user (MBP) and the booting time really surprises me.

Within few seconds, from complete power down, the OS prompts you to log in, then the rest just flies!

And even faster recovery from sleep mode.

I believe Mac OS is based on Unix BSD, so I'm wondering why we havent see such thing on Unix/Linux with similar hardware?
There are many factors that go into booting speed (age of computer, processor, hard drive type and speed). The biggest factor is that Apple has a closed environment and it's OS knows what to expect in terms of hardware and is optimized for that hardware. With Linux and Windows, there are many factors that the OS has to take into account driver-wise in order to optimize itself.