... in response to K-3, K-1, and service centers, posted by Rota20 on May 8, 2004Nebraska handles Missouri residents (initial petition) and then 'Missouri' (Chicago address!), the National Benefits Center, would handle the K3 petition, if any.
You can check where they are at here:
https://egov.immigration.gov/graphics/cris/jsps/caseStat.jsp;jsessionid=asKhroVXWTE_
There is essentially no difference right now in processing times. Estimate six months- although many things can slow things down.
Why is speed always the overriding concern?