My two cents:

First of all, pitting the load times of two very different operating systems against each other as if they were equals or even using the two in some vague point of comparison is completely irrelevant. The hardware specs they are running makes no difference either, because the software works and uses said hardware in totally different ways.

Additionally, any boot time for any computer running any OS that is less than a minute is pretty darn good. The four second variance you listed is far less time than it would for you to read this post, thereby making it a fairly negligible variance in my book. Four seconds of your time is not going to make or break a thing. Even sixty seconds of your time is not going to cause you any major delays or "waste" any time.

Lastly, the Mac OS is really meant to be running all the time. There is little need to ever actually shut down the computer completely. If you are going to be away for an extended period of time, simply put the computer to sleep. That way when you return, a tap of the keyboard or mouse will bring the computer back to a state of readiness almost instantaneously.