Simcraft:
This is the tool that is used to get our stat weights (aka PP). Unlike in previous expansions you can't easily run yourself through Simcraft to get customized stat wights. This is because there are simply too many variables that come into play with analyzing stat priorities / wights / breakpoints. There's the 9 combinations of talents, different fight types and two kinds of secondary stat analyses that all need to be taken into account. With a dedicated machine (aka the Blowtorch) it takes around ~24 hours of simulations to produce the stat weights.
That said it can be useful alongside the BiS Lists for evaluating some combinations of gear setups with the caveat that it is to be used as a tool, but not as a bible. You can download this program and find more information at:
http://simulationcraft.org/