I've been to Mateo's a couple of times. I don't love it, but it's one of the currently solid, hot Boulder places. We went on Friday night - strike one was that they blew our reservation which we made through Open Table. We were "unconfirmed" (although we had a printout from Open Table with our confirmation number) so they scrambled to put together a table for us. We were in the very back with a straight line to the kitchen and the bathrooms (both around the corner - but we had a lot of traffic all night long). The service felt a little slow at first - our waiter was very nice - but I consumed a loaf of bread and a french fry appetizer (yum - but very excessive since fries came with two of the main courses) before our salads came. My salad (they change regularly) was great - beets, watercress, and nuts. I had potenta for my main course - unfortunately the sauce was loaded with capers (which I hate) so I suffered through and just had the polenta chunks (lightly fried - pretty good, but not amazing). Dessert was a chocolate pot de cream and a cheese plate - standard high end fair (good, nothing special).
Overall, I find Mateo good but overrated compared to some of the other Boulder neighborhood choices. It's always busy on a weekend night so get a reservation if you are going to go.
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