Chase hard pulls for credit limit increases that you request. This dings your FICO score. In 2 years, I've never had a credit limit increase from Chase--even though I have a 765 FICO.
Their customer service reps are surly and rude. When I asked about a possible increase in credit without getting a hard pull inquiry he copped an attitude.
My advice is: if you have the Chase Amazon, it can't hurt to keep it if you don't expect much from Chase. But if you're shopping around for new credit, there are rewards cards out there that offer better service and are much more consumer friendly.