I highly recommend the Go Chicago card. I just got back from Chicago and five of us purchased the Go Chicago card before our trip which was on sale for around $95. We did two boat cruises, visited Navy Pier, did the Planetarium, Field Museum, Shedd Aquarium, John Hancock Center and an open air bus tour and saved approximately $75 each using the card. We were there for three and half days (card was valid for three days) and we all definitely felt we got our money's worth. If they are only there for a short time the City Pass might be a better value. There are also shopping discounts and dining discounts with the Go Chicago card.