Used it twice in Sao Paulo today, both cases uber black

Timing is great, the cars are very good (though what is uber black would be probable the equivalent of uberX/uberExec)
First driver (Toyota Corolla)did not speak english but had translation apps when they wanted to make themselves understood.
Second driver (Hyundai Elantra) did speak a little english and had some sweets and coolers.

Both drivers were using the Waze app for getting around the infamous traffic in Sao Paulo