I go to Zaba's so often that they know who I am, so I consider myself an expert.
The restaurant is always clean, even behind the counter. Service is quick (as it should be) and the staff members are always happy to help. It never feels fake or forced, and I always enjoy our chit-chat.
It's the Subway of Mexican food, so there's not a TON to say about it, but I can definitely recommend it. Clean establishment, quick service, good prices, and delicious food. One of my regular haunts!