We just got back from 2 nights precruise and 1 1 post cruise in Brickell. Did use the metro mover a couple of times. the trolley once (to Little Havana). Both of these are free but locating the trolley was a bit confusing. Booked the city bus but did not use; did not realize the “clock” starts once purchased online. The Miami transit system is great but you need to know beforehand where stops are located and whether it’s worth using over Uber. For example, had to walk 10 blocks to the Little Havana trolley and it had maybe 15 stops to get to Little Havana. An Uber would have taken 1/4 the time and costs maybe $10 from Brickell.
Versailles restaurant is great for cheap Cuban food and ideal to order several small dishes to see what you prefer. Almost always a wait outside for seating but worth it.