Mine took 3 weeks in 4/11 - I have heard it is taking longer now because more people are getting Nexus/GE so they can be eligible for TSA pre-check. I was able to get a Nexus interview within a few days at the Ambassador bridge in Detroit after conditional approval. When you go for your Nexus interview make sure they put the GE "CBP" sticker in the back of your passport (they sometimes forget).