I have experienced a few great Critical Mass rides. My personal top 3 would be Paris France, San Francisco, and New York City, but if Miami keeps it, they may be taking 3rd.
This past Friday when cities all over the world had their monthly Critical Mass ride, and Miami was sporting over 800 riders. As you can see in the videos below, the riders are full of energy and celebrating the bicycle, and they take over 6 minutes to go by! The Bike Miami Scene has done a great job of promoting Critical Mass and has listed out their purpose, rules of the ride, and have used media to get the word out. Good on you.