I went to Que Onda for lunch with a friend on a Sunday. It was pretty empty inside, and the service was a little slow. Most places uptown were closed at the time so I'm glad they were open and I'm guessing there was just a little less staff than usual.
We got guacamole, which they make at your table. It was excellent. I also got the steak quesadilla as my meal and although it is an appetizer it is definitely enough to be filling. The quesadilla was pretty good, and the side of fried plantains was delicious.
I really loved the decor, and it had a great local atmosphere. I wasn't super impressed, but I would go back (the taco menu looked delicious) and its definitely a solid lunch spot option.