Coverage.py v3.0 is done. There are new docs up, and final kits. The main change since beta 3 was how the standard library is excluded. I was being too aggressive, and sometimes excluding all the product code as well, depending on the layout of the project. Now it behaves much better.
If you haven't been keeping up with the changes since coverage.py 2.x, there are plenty of them, including greatly improved speed and a nice HTML reporting feature.