I grew up in Tampa, FL so I feel justified in claiming to know a thing or two about Cuban food. That said, Habana Libre was excellent and authentic.
The dining room has a comfortable vibe, a touch tacky (in a good way). The tostones (fried green plantains.... mmmmm yummy), yuca frita, croquetes, arroz con frijoles negros, and palomilla steak are particularly tasty. The service was really good, the staff is friendly and helpful... the prices were good.... what's not to like?!
Pros: good food, good service, good prices.
Cons: Getting to the west loop can be a pain, depending on where you're coming from