Nanny vs. Childcare
I need to start off by saying I don't use either of these because I work from home. BUT... If i did I think I would choose a Nanny. That way I'd could build a relationship with that person and I could think of them as more of a parenting partner then just someone watching my kid. I'd have more control over how my kid is raised, which is why I wanted to be a mother in the first place. I also like that the nanny could focus on just my kids. Childcare providers have to be divided by however many kids are in their room. I don't think that's a big deal for older kids, but when you have a toddler learning to potty train that one-on-one attention is critical.
The plus side to childcare is that it's generally cheaper and your kid would get a lot of socialization.