'Born This Way' is just instantly recognizable, it's one of the first things that come to mind when people think of Gaga. But B'Day just wasn't as omnipresent as Born This Way was. Both were big eras tho but I have to give it to Born This Way, especially globally.
B'Day. Both eras were very poorly received at the start, but Beyoncé turned that around with the song of 2007 in the U.S. and a Spanish language re-release to have the bigger era.