I know cobras is not TAC supported yet. But I have a install coming up and thinking of using it. Going from 4.x to 5.x. I would like use or try cobras, but also rather not because it's not TAC supported.
If the consensus is that it seems to the job, great. If it does not, then I will rely on DIRT or Digitally networking the (2) servers and using the subscriber migration tool to move subscribers over.