For the last few trips, I have always used either Uber or Grab when coming/going from/to Ho Chi Minh City airport in Vietnam.
Tourists are usually advised to only only use two taxi companies when in the city; Mai Linh or Vinasun. There are others as well, but if you stick with these two the chance of getting ripped of is very low.
Friend of mine had taken a cab from the taxi line at the SGN airport. The drivers had been rather aggressive and told her that she needs to take the next one available.
The driver had missed the entrance to Le Meridien hotel and the meter had been 980,000 VND that is roughly six times or more than what it should have been.
My Uber fare from the Renaissance to the airport was 82,000 VND and the regular cab fare should not have been more than 150K VND max.
My friend, however, was more worried that the driver would have dumped her somewhere else than the hotel.
These two taxi companies (Vinasun & Mai Linh) are the ones that usually have cars waiting outside at all the western branded hotel in the city.
It pays to be careful when choosing one from SGN and make sure that they actually drop you at your hotel. The hotel could have negotiated the proper fare or taken photo of the license plate.
It is unfortunate that these taxi scams around the world continue. It just means that more business for companies such as Uber and Grab.