My husband and I are considering a land tour of South America to see Buenos Aires, Rio, and Machu Pichu. There are so many tour companies - General, Gate 1, Monograms, Trafalgar, etc. Does anyone have a comparison of tour companies? Any thoughts on any of these? Initially we thought the individual attention of General Tours was appealing but then we thought it might be weird just the 2 of us in a car with a tour guide. Has anyone used General Tours and how was it?