Linux OpenGL: Ubuntu 13.04/13.10 vs. Fedora 19/20
Intel Haswell hardware benefits hugely out of Ubuntu 13.10 and distributions with more recent packages like Linux 3.11 and Mesa 9.2, since the hardware is still very fresh and Intel optimizations are still landing, but older Intel graphics cores along with Radeon and Nouveau GPUs should see nice improvements too thanks to other work like Radeon DPM, the maturing RadeonSI stack, etc.
For die-hard open-source users wanting the latest open-source graphics driver advancements on a non-rolling-release distribution while still staying fresh with new kernels, Fedora Linux tends to be the best offering.