If I have a Samsung GS6 which payment system should I use?

[AC Question]

Samsung Pay sounds more convenient when using a GS6 but I feel like Android pay would be better to use in the google ecosystem and might soon have rewards baked in to the payment system. Also not sure I could do this easily but could I use both and specify one over the other for everyday payments and then switch in case I am in a store that offers rewards through android pay. Thanks