I really didn't care much about Darla until we got to see her explored as a human so I have to go with human first. Season 1 of BTVS she was written terrible; in the flashbacks of season 1... okayish but still not much known about her but when we see her as a human in season 2, it makes us learn more about her and than of course we learn more about her as a vampire which I loved even more.

I loved the power couple Angelus and Darla was though and I'm still upset we never got at least one scene of how their reunion might be.