Got the same survey too!
Very interesting that Capital One MC is in the mix. AFAIK Capital One has the best foreign exchange rate on their Visa cards as they do not pass along the 1% Visa Network fee while Chase does. AMEX forex rate can be higher or lower than Chase rate based on observation. However MC has the best forex rate among all 3 according to the thread(s) focus on this in the Credit Card forum.
Capital One actually has a fairly decent customer service - no less than Chase and handles rental car claims far better than Chase, quite a pleasant surprise.
There is one question asking about whether one prefers a single card from AMEX or a Chase card for Marriott, an AMEX for SPG, and again a Chase card for Ritz.