I am going to have to vote for Potro... probably not very well known in the states. It is a local Guanajuato brew I had down there last summer. It is an English style stout and very good.
I had a beer in Mexico that isn't sold in the US (well it wasn't a year ago, haven't seen it though). It was either Victoria or Victorian, made by Corona. It was pretty good.
I will say that I learned a nice trick about cutting limes when I went to Cabo. I normally try to slice limes by cutting it in half and then making a triangular wedge along the axis.... THe problem came with sometimes I had a piece that was almost too big to get in the beer bottle which could suck. I'm trying to drink a beer and instead I'm trying to cornhole the beer bottle with a hunking piece of lime.
Well in Cabo, they did a few things different. First, they used Key Limes instead of Persian Limes (key limes are the tiny ones in the big bags, Persian Limes are the bigger ones I used to buy).
Second, they would almost cut the lime and make it square almost, but they certainly didn't worry about cutting it directly in half and making little wedges like that. THat's how I do it now and it's alot easier.