We just migrated our codebase from C++ STL to C++11 and in general, it was worth the pain.
The main benefits for us were better awareness of modern character encoding - but stuff like lamda functions are pretty cool too, and we could probably tidy up a lot of our earlier code to use more C++11 features.
I was brought up on Assembler (Z80, 680x0) and moved to 'C', and then migrated to 'C++', so my early C++ was very C-like (not unusual). However, I've not looked back. I know that you are asking about C++11, but C++ itself is probably worth highlighting.
I also know Java, Obj-C, (and a bunch of other languages that I have used in less commercially sensitive contexts) and there's a lot to be said for them too. But when I feel like getting close to the metal, it's C++ for me. I guess it's b/c one can still (just about) follow the assembler generated by it.
But then I'm old in my approach. Modern optimising compilers, with coding strategies, static analysis (as well as excellent IDEs) probably have more effect on my productivity than any language sub-variant.