The first thing we noticed upon leaving the airport is that locals are directed to normal looking taxis, while foreigners were directed toward shiny black lexus cars (clearly more expensive) and no choice was given in this matter.
The second thing we discovered about the taxis in Dubai was that none of them have a GPS system. Initially one might think that this indicates that the drivers really know the city well, however we found that was absolutely not the case.
One our way to our hotel, we told the driver the name of the hotel and showed him the address we had printed from our confirmation – he looked but clearly he did not really read it. Apparently we had actually booked a hotel in Sharjah (the next city over) and not Dubai (our mistake) but the driver took us to Dubai anyway because he didn’t actually read the address we showed him, and then complained that we told him to go to the wrong place. And he definitely overcharged us for that trip.
Another taxi ride from Dubai city center to our hotel, which should have taken maximum 20 minutes, took 1.5 hours! Apparently the driver had never been to Sharjah before (so we have no idea why he agreed to drive us there in the first place). He stopped for directions 4 times and still could not get us to our hotel! Finally we got out and changed to a local Sharjah taxi who got us to our hotel in 5 minutes.
So, my main advice about Dubai Taxis:
1. be sure your hotel is actually in Dubai and not in Sharjah or other neighboring area
2. try to have directions ready because the driver likely will not know how to get you where you want to go unless it is a top 10 touristy destination
3. get ready to be wildly overcharged if you are a foreigner