This is one of those questions that sounds like it should have a clean answer, and it just doesn't. People ask whether Uber or Lyft is cheaper in Miami expecting one of them to win, and the honest response after watching prices on both apps for a while is: it depends on the minute you hit the button. But there are some real patterns worth knowing before you assume the app you always open is the cheap one.
The short answer
On any given Miami ride, Uber and Lyft are usually within a few dollars of each other. Sometimes Lyft comes in five bucks cheaper, sometimes Uber does, and the gap almost never holds steady from one request to the next. So the money move isn't picking a favorite. It's opening both apps, checking the actual quote for your actual trip, and going with whatever number is lower right then. That sounds obvious, but most people don't do it. They open one app out of habit and eat whatever it shows.
Where it gets interesting is the situations where the two apps consistently diverge, and there are a few of those in Miami.
Airport rides: check both, every time
Coming out of MIA is where the difference actually shows up, because both apps stack an airport pickup fee on top of the fare and then surge on top of that. A ride from MIA to South Beach runs somewhere around $34 to $46 on UberX during normal hours, and Lyft lands in that same window. During a surge it can climb toward $90, and this is exactly when the two apps stop agreeing. One will be surging harder than the other depending on which one has more drivers sitting at the airport queue at that moment. I've seen the gap hit $15 to $20 during a bad surge, which is real money for a ten-mile ride.
The longer the airport trip, the more the surge gap matters. A run from MIA up to Fort Lauderdale is already a $69 to $93 fare before anything goes wrong, and when I-95 backs up in the afternoon both apps can push past $130. Checking both there isn't about saving three dollars, it's about not overpaying by thirty.
When Lyft tends to win
Lyft has historically leaned a little cheaper on shorter in-city hops in Miami. Think Brickell to Wynwood, or a quick run down to the beach. Not always, but often enough that if you're doing a two-mile ride it's worth a glance. Lyft also runs promos and ride-credit offers pretty aggressively for people who don't use it much, so if you're an Uber regular, your dormant Lyft account might be sitting on a discount you forgot about.
When Uber tends to win
Uber usually has the deeper driver pool in Miami, and that matters most during peak demand. When it's 2 AM in South Beach and everyone's trying to leave at once, Uber often surges less simply because it has more cars to throw at the problem. Uber also has more vehicle tiers here. If you want something bigger or nicer, Uber Comfort, XL, and Black are all easier to find, and Lyft's equivalents are thinner in this market. For a group with luggage, an UberXL split three or four ways usually beats everyone taking separate cars.
The surge is the real story
Here's the thing nobody wants to hear: whether Uber or Lyft is cheaper matters way less than whether you're riding during a surge at all. A few dollars between apps is noise next to a 2x multiplier. Miami has some very predictable surge windows. Weekday afternoons on I-95. Late nights in South Beach and Wynwood on weekends. Anything happening at Hard Rock Stadium or the Kaseya Center. Art Basel week in December is its own special kind of chaos where the whole city surges for days.
If you can shift your trip out of those windows even by half an hour, you'll save more than app-shopping ever gets you. And if you can't, because your flight lands when it lands, that's the scenario where a pre-booked fixed-price transfer starts making sense. The quote is locked before you fly, so a surge that would've turned a $40 ride into a $90 one just doesn't touch you. On the shorter in-town trips a rideshare is almost always cheaper, no argument. It's the airport runs during peak hours where locking a price in pays off.
So, which one?
Install both. Actually use both. For a normal off-peak ride, pick whichever quotes lower and don't overthink it, because the difference is usually a couple of dollars. Lean Lyft for short in-city hops and check it for promo credit. Lean Uber for late-night peaks and anything needing a bigger or nicer car. And when you're landing at MIA during a known surge window, compare both against a fixed-price transfer before you commit, because that's the one case where neither app is the cheap option.