It seems that I'll be the outlier, but I've had better luck through PHL.

Each time I've come through CLT the flight was early, and we had to wait on the plane until CLT customs & immigration opened. It was just a few minutes once, the other time it was a good 30-45 min. Then when we did get off the plane, there were 2-3 other plane loads of passengers all running with us to get to immigration first.

There just don't seem to be enough immigration officers at CLT either. I've always had to wait, sometimes as long as 30 min.
At PHL, if I don't walk right up to the agent, the wait is no more than 5 minutes.

The luggage... Same thing, I've always had to wait longer for bags at CLT, where they seem to come out fairly quickly at PHL.


And lastly, getting back through security to catch your connection. While I'm sure you can use different checkpoints at CLT, they steer you toward one with few screeners. Seems to take another 20 min.
At PHL they do have the transfer screener (which only has a few), but you can bypass that and go to the normal line. I've never had to wait more than 5 min at PHL.


I think US has put too many international flights into CLT and the airport just isn't fully prepared for them.
PHL has had a similar volume for a while and seems better at handling them.