Nicolas took us on an absolutely perfect tour of Buenos Aires. Focused on culture, history, and architecture, we walked through the La Boca and San Telmo neighborhoods, then to the Plaza de Mayo. (You can pick other areas if you wish; these were the ones we chose. Wherever you go, wear good shoes -- we did -- because the sidewalks are uneven.)
Nicolas was incredibly knowledgeable, friendly, and adaptable. He helped us see things that we would otherwise certainly have missed, and was happy to adjust to our pace. We enjoyed him tremendously and recommend him highly.