My husband traveled to the US in December (both for work and holiday) and it was no problem (all of our paperwork had been submitted and we were waiting for our interview date). He made sure to bring a letter from his employer stating that he was expected to return to work in Ireland. In the end, he had no issues getting in and his visa has since been approved! Here is the guidance that is on the US Embassy in Dublin's website:http://dublin.usembassy.gov/faqs_immigration.html#question20Can I travel to the United States while my application for an immigrant or fiancé(e) visa is being processed?
If you intend taking up permanent residence in the U.S., you are required to wait until the immigrant or fiancé(e) visa is issued. You cannot reside in the U.S. on a tourist visa or visa free under the Visa Waiver Program while waiting the processing of an immigrant or fiancé(e) visa. However, if you wish to make a temporary visit at the end of which you will return to your permanent residence outside the United States, you may travel on a tourist (B-2) visa, or visa free under the Visa Waiver Program, if qualified.
If applying for a B-2 visa, you are required to furnish evidence of your residence outside the United States to which you intend returning at the end of your temporary stay. Although a pending immigrant or fiancé(e) visa application is not necessarily conclusive evidence of intent to abandon a residence abroad, it is a factor considered by consular officers reviewing a visa application. If you are unable to convince the consular officer reviewing the application that you do not intend abandoning your residence, you will not be issued a visa.
When traveling to the U.S. either with a visa or visa free under the Visa Waiver Program, you should be sure to carry with you for presentation to an immigration inspector evidence of your residence outside the U.S. If the immigration inspector is not convinced that you are a bona fide visitor for pleasure, you will be denied entry into the United States.