All ATP's Fort Lauderdale
L-13, I used ALL ATP's when I did mine. I used ASA iPad app for a bit of light reading prior to getting there.
They sit you in front of a computer for 8hrs with access to all the questions and when you are getting mid 80's they then give you the test.
Don't expect any help or useful info from anyone there. They are there to turn the computer on at the start and turn it off again at the end.
A bit sausage factory-ish and not really sure what you're meant to remember from the exercise, but you will almost certainly pass.
I found the biggest differences from Europe/Oz is the pt121 fuel planning and the fact that wx reporting, W&B, Perf and viz are in SM, ft, inches,Lbs and US gall.
If you read over that before heading off state side you will do yourself a huge favour.
Also make sure you take an electronic flight computer with you.
PM me if you want further info.