I had lunch here earlier today and was not impressed. I was shocked to read reviews for the other locations in the Phoenix area but maybe the Glendale location just isn't up to par.
It is not bad in any way, but it is also not special either. I did enjoy the three dips (chunky salsa-mild, chili salsa-hot and beans) and chips. I also liked that the menu had a picture of each item so there wasn't going to be a surprise in that arena of the situation.
I ended up ordering an enchilada and two flautas. They were average- nothing to write home about or to be angry about. Just, eh, there.
Our waiter was attentive and brought us what we needed. The decor is festive and bright. Arriba seems to have some of the right things going for it, so I might have to return again to give it another chance.