I thought for the longest time that Carlos O'Brien's was an Irish pub, so when I friend called me to meet up there It was a complete surprise when he told me that it was actually a Mexican restaurant.
I thought the staff was very friendly and welcoming, but really the vibe of the place does not feel like a Mexican restaurant at all until you see the menu and taste the Frozen margaritas. The waitress kinda looked at me like an airhead when I asked her if they had blended margaritas but once she said Frozen she knew what language I was talking.
Their happy hour isn't bad. My chicken quesadilla was a disappointment as it did not come with any sour cream, salsa or guac. The salsa that actually came with the complimentary tortilla chips was rather a disappointment and completely lacked in flavor.
My advice if you want a great atmosphere and also a great patio with some great Mexican fare and great service, go north to Jalapeno Inferno!