Private Remise which is bookable immediately after exiting customs is the best way to go. Taxis at the curb after exit but that might entail a significant wait. There are also shared van transports (which are also bookable at the desks after exiting customs) about which I know nothing but you can take a look at www.tiendaleon.com.ar

Under no circumstances should you accept a ride from anyone who solicits you inside the arrivals hall. Use only official services at the transfer desks or the radio taxis lined up outside.