I've been to Gia Lai twice now and while I can't say it's the most authentic Vietnamese food I've ever had, the restaurant is beautiful (the ideal respite from a day of shopping at Legacy) and the servers are friendly.
It's nice to have some lighter menu options (spring rolls and salads) as well as some filling dishes (pho). Again, the options aren't authentic, but when you're looking for Asian fare in the area this is a heck of a lot better than Sushi Rock down the street.