folks skip the other "fake" mexican places. This is the only one in south beach you should visit.
Location: Right at the end of lincoln road mall. a $3 uber from any south beach hotel or a 6 short block walk
Service: Always excellent, I have eaten at the one in NYC near lincoln center and same consistent attention to detail.
Food: the Best - must have is table side guacamole, to die for...get extra spicy. Serious, the food is authentic and fresh. You know this by all the folks from Mexico that eat there.. the are my references. I had the shimp entree 6 big fat shrimp. well worth it for $21 buck
Value: it won't break your wallet , good reasonable prices.