Last year I flew into Newark coming back from Europe and it was a nightmare getting through immigration and security. Is Atlanta quicker? Arthritis makes standing in long lines very painful.
I never have a problem with long lines at Newark immigration or security, but if you have a medical issue like that simply tell the attendants controlling the lines. They're usually sympathetic, I've seen them move others to front lots of times.
I've only been through Newark a few times, but a lot through Atlanta. Atlanta is much better.
Atlanta is probably better, but you can check for yourself. http://apps.cbp.gov/awt/ You can see wait times online in the US Customs and Border Protection website. Since most of the flights are regularly scheduled, you can pick an arrival (at any airport) during a time when waits are short (only a few international flights arriving during that time).
I do both quite a bit. They can both suck but on average, Atlanta sucks much less with the exception of the rechecking of baggage. Depending on when you fly, ATL is about to open a new international terminal (this spring?) that's supposed to make everything 10 times easier. Not holding my breath on that one, but I doubt they will make it worse. Good luck!
Larry If making the long walk from your gate to immigration and security and standing is that difficult, you can ask the stewards on the plane to request a wheelchair before you land. Someone will meet you at the gate and you will be whisked through both. It is a nice quick way to get out of the airport without pain. Bobbie