Miami soil is going to be tough on citrus. Most of it is marl, which is basically a high-ph clay. It lacks drainage, and it's essentially impossible to drop the pH. Horrible stuff to grow in, but makes a great base for footings, slabs, etc.
North of Miami-Dade generally has much better soil. With a good fertilization regimen and consistent treatment for insects, citrus is very viable.
I know a lot of the folks on this forum are afraid of systemics, but imidacloprid is a good option for keeping your citrus free of insect problems. All of the citrus trees for sale in the state of Florida are treated with imidacloprid (it's an ag regulation to prevent the spread of greening). That's why they look so nice for the first few months after you bring them home.
As far as I know, a high percentage of the conventionally grown produce is treated with imidacloprid. Moreover, it's the main ingredient in the more popular flea and tick products that we give our 4-legged pets. I don't think it's that big of a deal to use on your citrus trees, and it's certainly far less labor intensive.