According to Google Ngrams eggplant is far more common (although in British English aubergine seems to have a small advantage over eggplant).
So, not being a native speaker of English I wonder whether using the word "aubergine" would be considered smug or weird by native speakers.
The thing is that I find the word "aubergine" a bit more natural because it's basically the same as in German (Aubergine) -- which happens to be my native language.