The Zoldyck Family arc is definitely my least favourite. But it's so short that there's simply no time to get bored, so that's good. I'm not sure if Togashi intended the arc to simply be an introduction to the Zoldycks or if he had bigger plans but simply wanted to move on to the next arc.
Anyway, Killua's conversation with Silva is probably the highlight for me. Even though Killua doesn't appear that much, it's mainly him that is in focus. Killua is my favourite of the main characters and it's nice to see his interactions with the other family members.