Have you driven in Brazil before?
Do you know the city well?
Do you speak Portuguese?

If the answer is no to any of those I'd suggest you are better off taking a taxi.

It depends on where you are staying and where you need to get. The city is crowded and the roads are congested. On the other hand, the city is pretty small. We rented a car in Manaus and had no problems though it is a tad unusual to see armed military police at the occasional road block. If you opt to use taxis, always get a receipt. The receipt will allow you to file a complaint with the Consumer Protection Department who will follow up with the driver. However, if I were on business, I think I would opt for a car and driver. Much more convenient.

while awaiting our Amazon guide and his boat, we were staying at the Hotel Tropical, then owned by the now-defunct Varig Airlines. We taxied to Manaus and having driven in dozens of countries worlwide, I can unequivocally say, NO!to driving in Manaus. a "jungle" within the jungle...city of well over 1,000,000 and everyone drives at the same time, it seems! Hire a driver.

Note:While in Manaus, be sure to see the 19th century opera house..it is so imposing you can't miss it from many parts of the city.

always just do driver/guides of quality through my nice hotel

use only LABELED cabs ideally from stands if u must

do not share cabs or rent a car lots of risk

insuremytrip.com travel.state.gov Brazil always wise

many scammers thieves shysters on line touts

including expats so BE CAREFUL always pay with CC

NEVER wire money have seen folks lose thousands.

barzilnuts.com brazilforless.com good info.

Happy Planning!

Crimes of opportunity, i.e., larceny, purse-snatching, armed street robbery, car theft and carjackings, pose the greatest threat to foreign visitors in Brazilian cities. Most foreign visitors dress differently and do not speak the local language. This increases their chances of being seen as a foreigner, and therefore perceived as an easier, wealthier target for criminals. Visitors are encouraged to keep in mind the following basic security precautions:

Avoid going out alone, if possible walk with a companion.

Avoid unlit areas, especially alleys and parks.

Do not resist an armed thief. If robbed, never pursue on foot.

Do not carry large sums of money; carry only what you need.

Do not wear ostentatious jewelry of real or apparent value.

Do not overburden yourself with bundles.

When riding in a vehicle, including taxis, keep all doors locked and windows rolled up to within two inches of the top frame.

The level of police assistance in these cities is described as marginal. Police response time is often lengthy due to the limited number of units available for patrol. Investigative efforts often are found lacking due to a high number of daily incidents, and a lack of available manpower needed to investigate those incidents. The local forces suffer from inadequate levels of training, manpower, lack of proper equipment and notoriously low salary levels at nearly every rank. Together, these factors help fuel the low levels of morale among the officers, which is directly reflected in the level of service provided.