Originally Posted by corporate-wage-slave

In your shoes, I would certainly go landside, it's a lot quicker from DUB, and then indeed pass by the visa check desk before going to the barriers at Security. There usually isn't a queue at the visa check desk, you more or less have to walk past it anyway, so no matter what they do at DUB you should swing past and get them to scan your passport for ESTA verification. It makes no difference if it is done twice, but it makes a difference if it's not done at all.