It's like asking "either the 101 or Pacific Coast Hwy to San Francisco?".
Guess the answer depends if your in a hurry, or want to enjoy the view.
Glad you took the inside route. Sometimes the light makes the little islands glisten like Emeralds. There's so many nice places to hang out and visit between the Channel 5 bridge and Miami, that one can spend months just cruising in between. There's a GREAT 24 hour store/Deli in Islamorada that you can access via Coral Bay Boat Yard (right south of the Lorelei) to re-stock. Lot of good snorkeling on the ocean side, that you can access from the bay side by tender. Bars, Restaurants on both sides. You can go way NW off the line and find places to anchor in total privacy for weeks at a time. The water used to be crystal clear the whole route. You could see a dime on the bottom in 10' of water in Jewfish Creek, where Gilberts has GREAT food, and the condo across has reasonable dockage (if any dockage down there could be called "reasonable") vs. Gilberts. Lots of good anchorages all the way up too, and including Miami.