Haiku is the underdog that just keeps on moving forwards. Every release it gets just a little more complete.

There is a vital lesson in Haiku OS. If you benchmark anything on it, it isn't the fastest thing around. Compiling code is about 40% slower than Linux for instance (which is still impressive). But the user experience is absolutely divine. It is the benchmark for responsive UI and it should be a mark of shame on Apple, Microsoft and many Linux desktops that they are being out done by such a small team.