I think it is really matter of an opinion, there is hardly a right answer.
In my experience with writing portable Win32/Linux server code (15+ years), I personally find boost/ACE unnecessarily bloated and introduces maintenance hazards (otherwise known as "dll hell") for the little advantage they give.
ACE also seems to be horribly outdated, it is a "c++ library" written by "c programmers" in the 90-s and it really shows in my opinion. It so happens, right now I am re-engineering the project written with Pico, it seems to me it completely follows the ACE idea, but in more contemporary terms, not much better at that.
In any case for high performance, efficient, elegant server communications you might be better off not using any of them.
