if you're trying to write platform independent code and already using boost, then it's a strong incentive right there, to avoid #if PLATFORM do this #else do something else, #endif, etc.

A previous employer of mine had used Boris's directory monitor service code. However there were some issues which we had to work around. I don't remember what they were. Unfortunately I no longer work with that employer so don't have access to the source code to jog my memory. It might have simply been the way in which we were using the code.