Of course, if you assume it's a Windows application...
I usually go for the portable solution if it does the same thing as the unportable one.
From the Boost homepage, the second line
It points out 4 things that make it different from WinAPI - free, peer-reviewed, portable, and open source. If those things are not important to you, Boost is probably not for you, but that doesn't mean other people don't value those things as well.Boost provides free peer-reviewed portable C++ source libraries.