I currently use the following cards:
Groceries & Gas: American Express Blue Preferred (6% and 3% respectively)
Restaurants: Citi Forward (3 points/$)
Travel: Chase Sapphire and United Mileage Plus


For everything else, I use the Fidelity Amex which is 2% cash back on all purchases. However, I have problems having it accepted at some places so I have to use another card at 1%. Now, Citi just came out with the Double Cash, which is also 2% cash on everything. Since , it is Mastercard instead of Amex, I'll have almost universal acceptance. Is it worth switching? If so, should I cancel the Amex or just shove it in a drawer? Is their another card I should consider instead? My goal is to have a minimum of 2% cash back or equivalent in points for all purchases.

Thanks!