The Octagon
Stop...Hammertime
Really?Buffy fights a genocidal war, killing first and asking questions later. She knows that demons can be good guys but she will still behead or stake them without hesitation. She's occasionally nice to her mates though.
It's a bit apples and oranges to be fair, but the human trafficking / lack of free will aspect (Echo and the other dolls are used as basically sex slaves on several occasions) of Dollhouse make it a little more uncomfortable viewing (IMO).
There's still some humour, but it's definitely scaled back compared to Buffy / Angel, etc.