They seem pretty much the same to me too, so I don't personally have any objections to mixing in BSD code with MIT. But I'd like feedback from others 🙂
I am also willing to consider accepting GPL code, but that may be more controversial. If I remember correctly, the reason OpenBeOS/Haiku originally wanted a MIT codebase is because it didn't require derivative work to be open-sourced, and the team had hoped some corporation would step in an continue BeOS and leverage some of the OpenBeOS code. At this point I think it's unlikely there will ever be another major commercial OS so it seems like a moot point.