I think these rankings are useful mainly for identifying programs to apply to that you wouldn't have otherwise thought of. As an alum of the Maxwell School at Syracuse, I have no illusions that my MPA is somehow seen as more prestigious than a degree from HKS or Princeton - it's definitely not. But it wouldn't have occurred to me to look into applying if it wasn't for the US News rankings.
No employer will care about your school's public affairs program ranking in US News. They're not going to look up the most recent ranking when deciding who to interview. Many (particularly private) will care about the brand name of the university, particularly if it's an Ivy. Other than that, it's really about the network, and the rankings can give you a sense of how well-established a program is. More established programs are likely to have better networks.
My advice is use this list to identify programs to research and apply to the ones that best fit your interests and preferences.
