Compiler support for them is still a problem, and I don't want to bring in boost as a dependency. But then again, it's hard to find a thread library that goes beyond the *nix/Windows world, so I might just unroll my own code for conditions and semaphores.
Gcc has had reasonable C++11 support since ~4.7, clang since ~3.4 and visual studio since v2013 and even Intels compiler and IBMs are not too far behind the game. Good C++11 support has been available on most platforms with multiple compilers for years. There's no excuse for not moving to it (IMHO) - especially since it's such a huge improvement over C++98.
And your comments about being scared about the mem allocations etc that you cannot see; in my experience you should be more scared about the manual memory management code you write yourself. Chances are good that the C++ standard library got it right and you'll get it wrong.