Fantastic. Anything involving any members of the Fanged Four interacting has always been my cup of tea, but I'll admit to having a soft spot for the Spike and Darla relationship--mostly because there's so much to explore there since canon barely addresses it.

And this was very realistic: despite the chip and the mortality, they're still family, still who they are, even if they're not happy about that. Your characterizations were spot-on. I loved it.