As cool as steam-punk is, the Borg seem to be no more than a steam-punk version of the Cybermen. They have their moments, yet none that actually distinguish them from being just a copy of the Doctor Who villains. It's almost as if the power of the Cybermen infested yet another universe.
The Borg and the Cybermen are different in a lot of aspects. Yes, the have several similarities, but ultimately, they are not the same. I think the creator of the Borg created a new and unique species. They are still visibly human, rather than the Cybermen who are practically just robots using the human brain as a tool. The Borg assimilate and require a special environment to live in, whereas the Cybermen just take what comes their way. (From what I know) The Borg are an alien species while the Cybermen were created from humans.