The Woman in The Hat, who's rarely met a (non-Asian) duck she didn't like, and who ranks Frank B's duck high on her "best of all time" list, had duck at Brigtsen's w/ cherry sauce on Wednesday last, as she always does when we're in NOLA.
Thursday, she was kind of under the weather, (a bad oyster maybe?) and so did not join us at Upperline, where we had never been previously. In her absence, I preemptively tried Ken Smith's duck there. Wow. My immediate comment was "I gotta get her in here, before we leave town!"
We had a non-specific dinner invite for Saturday. When asked if there was someplace we'd specifically like, I said "Yep. Upperline!"
The intervening passage of several days prevented a really clear A-B comparison (to use an audio geek term) but the balance may now have shifted in favor of Upperline.
I'd say go with the port-garlic sauce, rather than the peach, though they'll bring you both.
This is why, btw, I had my blood tests for my 6/1 physical taken two weeks earlier, BEFORE I came to New Orleans.