We are so glad that we hired Luis to take us around Rio for the day. He is very knowledgeable of many things, and was able to answer all of the questions we had during our tour, including our strange questions. We loved how he knew where to take a photo and at what angle (like at Disneyland, where you see Kodak moment stands and the sign showing how to point the camera to take a photo). Our photos with the Christ statue turned out great because he took pictures of us while lying on the ground. We were able to cover way more ground than we would have had we did a bus tour. Plus, it calculated cheaper for us since Luis charges by car, not by person like those bus tour people charge. Rio was extremely hot and his nice a/c was a live saver. Hiring a private tour guide is definitely the way to go. Luis was quick to respond to my e-mails when I was trying to book a guide - this is the reason why I picked him over the others.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.