I use python for build automation, custom build jobs, code generation for C++, glueing command-line tools together and for multi-platform shell-scripting. For that it is really great. I also had some tasks where vanilla python was simply too slow. In this case I found it easier to move the slow parts into a small cross-platform C++ command line tool and call that from python instead of trying to make the python code faster. YMMV of course :)