ATM, any Python Scripts that you depend on will not work unless they are updated by the vendors or you recompile to work in P12. Something is up with some of the shader nodes not reproducing renders similar to P11, those need to be worked out also. Remember, the software, as is, is an Early Adopter, many features still need to be worked out, and we will see several updates down the line. I would hold off if you are looking to start off rendering images immediately until all the bugs are worked out. Go through the forum, you will get an idea of what's going on.