re: anyone ever clear customs and immigration in Atlanta...

I'd guess close to an hour. Went through there a few months back.

The passport review went pretty fast, but then all folks getting on a connecting flight had to go through metal detectors and screening, take off shoes, etc. like a new arrival. They say it's because you were reconnected with your checked bags and might have taken on banned items from your bags. That took as long as anything.

They did have plenty of people telling you where to go, etc. at each step of the way.