FYI:
I recently had a bad UberX experience in Sao Paulo. I was at a hotel and trying to take an Uber to GRU. The driver kept circling and wouldn't stop at the hotel (from what appeared on the app). After waiting over 20 minutes longer than the estimated time for the driver to arrive, we ended up cancelling and took a taxi for double the price. My only reasoning for this is that the driver was afraid to pick us up from a hotel; especially considering that there were many taxis out front waiting. Unfortunately, my Brazilian number isn't in my Uber profile, so I couldn't call the driver to figure out what was going on (and you apparently can't change your number very easily while on the app).
Something to consider if you're using Uber and your pickup location is a hotel.