Ugh, Buffy. I tried running a Buffy game but...players ran me right off. I hate to be "that guy" but every day was something new and horrible for me to deal with. I allow Highlander Style immortals but that's not good enough, I need to allow 1,200 year old Highlander style immortals who get extra points for combat stats you know, for reasons.
I allow player created demons with very few restrictions...welcome to the club of all combat stats getting straight +5's and every demon being immune to all types of damage.
It was a nightmare running that game for even the brief time I ran it. Everyone wanted to be THAT special snowflake.
While that is not entirely fair (I did run into a number of great people and had some good scenes) I would warn anyone looking to get into a Buffy game that "special snowflake syndrome" will run rampant.
All that said I do have a Buffy game kind of ready to go and would be willing to host it and work with people on it. I just won't run it myself.