Nothing to be impressed about. Micheladas have been around for a long while, and they are a good thing to do with weak, cold beer. I had one in Mexico about ten years ago and have been ordering them in Chicago (at Mexican-Mexican restaurants) ever since. No one ever made a big deal about it. In Acapulco a bartender claimed that a "regular" michelada is beer with a good dose of salt and lime over ice. A "michelada Cubana" adds hot sauce, Worchestershire sauce and whatever else the guy comes up with including, possibly, sangrita (the pomegranate and chile-based tequila chaser that many assume is based on tomato but should not be).
I have heard that micheladas are a true Tex-Mex invention concocted on oil rigs in the 50's or 60's, which sounds plausible. I know a lot of Southerners who put salt in their beer on a hot day.
I know they are GWiv approved, too.