I am a Romanian citizen and I have recently acquired Hungarian citizenship as well. I was never a resident of Hungary. I have valid passports from both countries, but I have never used the Hungarian one.
I have been to the US on multiple occasions in the past, both on short term (B) and long term visas (lived there for a few years). I have always used my Romanian passport. In fact I did not have the Hungarian citizenship when I last applied for a US visa, so border control don't know that I have dual citizenship.
Using my Hungarian passport (but not the Romanian one!) I can now travel to the US without a visa, under the Visa Waiver Program (VWP). Should I expect any problems if I do this? Based on my fingerprints (or just my name), border control may notice that last time I entered using a passport from a different country, and I worry that this will cause trouble (though I don't see how it would be breaking any rules).
Normally I would apply for a visa and use my Romanian passport, just in case. But this time using the VWP could save me a lot of time (which I'm short on at the moment).