As I stated in my initial respinse, having lived on the East Coast, primarily NYC and New England, my entire life, until now the only pronunciation I was familiar with was that the u had a y sound, not a soft u which would not require an. Since I now know it is an "ooh" and not a "you" sound, I would definitely use an and will do so from now on should I ever find it necessary.
Having been labeled a grammar Nazi by friends as well as some not-so-friendly people, I would be the last person to use an incorrect article based on spelling alone. I love and respect the English language and would feel terrible if I didn't speak and write as correctly as is humanly possible. This includes answering the question "How are you?" with "I am well." Sadly, I have come across very few people who don't say "I am good."
I was fortunate enough to have had amazing English teachers throughout my life, including several nuns. I also spent 30 years as a medical transcriptionist and knew how vital it was to both the patient and the dictating physician that my reports be as accurate as possible; this included not only spelling but grammar and punctuation as well.