I think that ultimately, assuming nothing else major occurs, that the dissolution of the EU will be a positive for just about everyone. During the process, however, I believe that world markets will be in a very up/down situation with wide swings for no discernable reasons.
Some imports from the different countries will go up, some down. Just like the market there for US products will vary widely from what they are now.
Travel will be a real pain as the borders are 'reestablished' and things set back up to monitor and control border crossings.
I do not anticipate much other impact here, except for the political aspect, as various faction in our government use the event to further their agendas in any way they can.
Just my opinion.