Both taxis and pre-booked transfers will get you from SYD to your destination. The question is which one makes more sense for your situation.
Taxis at Sydney Airport
The taxi rank is directly outside the arrivals exit at each terminal. During busy periods, there is a queue managed by rank marshals. Wait times range from immediate to 15 minutes depending on the time of day. Most taxis are sedans, though maxi taxis are available if you ask.
Fares are metered. A trip to the CBD costs AUD 45-65, and you pay what the meter shows plus any tolls. There is an airport pickup surcharge of about AUD 4. Payment by card is standard.
The main advantage is that you do not need to plan ahead. The main disadvantage is uncertainty -- you do not know the exact fare until you arrive, and during heavy traffic the meter keeps running.
Pre-booked Private Transfers
With a pre-booked service, a driver is waiting for you when you walk out of arrivals. They track your flight, so delays do not matter. The price is locked in at booking time, meaning tolls and traffic do not change what you pay.
A sedan transfer to the CBD runs AUD 75-120. You can request child seats, choose a larger vehicle, or specify meet-and-greet preferences. The driver helps with luggage and takes you directly to your address.
Where Each Option Wins
Taxi wins when: You are a solo traveler with light luggage during off-peak hours. The fare will be reasonable, the wait will be short, and you do not need to have planned anything in advance.
Private transfer wins when: You are arriving on a long international flight and want someone waiting. When you are traveling with children and need car seats. When you have more than two large bags. When your flight lands late at night and you want guaranteed transport at a known price. When you are heading to a suburb rather than the CBD, where metered fares can add up unpredictably.
The Price Gap in Context
A taxi to the CBD might cost AUD 55. A pre-booked sedan might cost AUD 90. That AUD 35 difference buys you a guaranteed price, flight tracking, meet and greet, luggage assistance, and a known vehicle. For some travelers, especially after a 14-hour flight from Europe, that premium is well worth paying. For a quick domestic hop from Melbourne with a carry-on, the taxi is perfectly fine.
Rideshare as the Middle Ground
Uber and similar services split the difference. They are cheaper than private transfers (AUD 35-55 to the CBD) and offer app-based pricing transparency, but they lack flight tracking and the driver will not come inside to meet you. Surge pricing during peak times can erase the cost advantage.