Uber is also safer, they have computerized records of your interaction with them and in spite of CR's false accusations, they are vetted by the company.
I've heard some horror stories with taxis, like driving to areas where their buddies rob you and pretend they know nothing about it and were victims as well, and later get their cut of the loot.
I also found uber drivers more professional, more courteous (you get to rate them after the trip) and nicer newer cars with air conditioning. You can lock the doors driving through shanty town and on the highway not get all that hot air in your face.
My experience with cabbies here is many will at least rip you off if they detect a newbie and drive an extra couple miles the long way and run up the meter, and many rig that meter so gringos pay more.
Many taxi drivers I've had were nice and honest, but many lied through their teeth, and more than a few endured my furious rebukes and then suddenly remembered where our destination was...
